MIC5013 [MICREL]
Protected High- or Low-Side MOSFET Driver; 受保护的高或低侧MOSFET驱动器
| 型号： | MIC5013 |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | Protected High- or Low-Side MOSFET Driver |
| 文件： | 总16页 (文件大小：155K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC5013
Protected High- or Low-Side MOSFET Driver
General Description
Features
The MIC5013 is an 8-pin MOSFET driver with over-current
shutdown and a fault flag. It is designed to drive the gate of
anN-channelpowerMOSFETabovethesupplyrailhigh-side
power switch applications. The MIC5013 is compatible with
standard or current-sensing power MOSFETs in both high-
and low-side driver topologies.
• 7V to 32V operation
• Less than 1µA standby current in the “OFF” state
• Available in small outline SOIC packages
• Internal charge pump to drive the gate of an N-channel
power FET above supply
• Internal zener clamp for gate protection
• 60µs typical turn-on time to 50% gate overdrive
• Programmable over-current sensing
• Dynamic current threshold for high in-rush loads
• Fault output pin indicates current faults
• Implements high- or low-side switches
TheMIC5013chargesa1nFloadin60µstypicalandprotects
theMOSFETfromover-currentconditions.Thecurrentsense
trip point is fully programmable and a dynamic threshold
allows high in-rush current loads to be started. A fault pin
indicates when the MIC5013 has turned off the FET due to
excessive current.
Applications
• Lamp drivers
OthermembersoftheMicreldriverfamilyincludetheMIC5011
minimum parts count driver and MIC5012 dual driver.
• Relay and solenoid drivers
• Heater switching
• Power bus switching
• Motion control
Typical Application
Ordering Information
Part Number Temperature Range
Package
MIC5013BN
MIC5013BM
–40°C to +85°C
–40°C to +85°C
8-pin Plastic DIP
8-pin SOIC
+
V =24V
+
10µF
MIC5013
8
7
6
5
1
2
3
4
Control Input
Input
Fault
RTH
Thresh
Sense
V+
SR(
+100mV)
VTRIP
20kΩ
RS
=
Gate
R I – (
+100mV)
VTRIP
L
Source Gnd
+
SRRS
V
IRCZ44
R1=
(S=2590,
100mV (SR+RS)
R=11mΩ)
2200
SOURCE
RS
RTH
=
–1000
SENSE
KELVIN
VTRIP
43Ω
LOAD
For this example:
R1
4.3kΩ
IL =30A (trip current)
V
TRIP =100mV
Figure 1. High-Side Driver with
Current-Sensing MOSFET
Protected under one or more of the following Micrel patents:
patent #4,951,101; patent #4,914,546
Note: The MIC5013 is ESD sensitive.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
July 2000
1
MIC5013
MIC5013
Micrel
Absolute Maximum Ratings (Note 1, 2)
Operating Ratings (Notes 1, 2)
Power Dissipation
+
Input Voltage, Pin 1
Threshold Voltage, Pin 2
Sense Voltage, Pin 3
Source Voltage, Pin 4
Current into Pin 4
–10 to V
–0.5 to +5V
–10V to V
–10V to V
1.25W
100°C/W
170°C/W
θ
θ
(Plastic DIP)
(SOIC)
JA
JA
+
+
Ambient Temperature: B version
Storage Temperature
Lead Temperature
–40°C to +85°C
–65°C to +150°C
260°C
50mA
–1V to 50V
–0.5V to 36V
–1mA to +1mA
150°C
Gate Voltage, Pin 6
+
Supply Voltage (V ), Pin 7
(Soldering, 10 seconds)
+
Fault Output Current, Pin 8
Junction Temperature
Supply Voltage (V ), Pin 7
7V to 32V high side
7V to 15V low side
Pin Description (Refer to Figures 1 and 2)
Pin Number
Pin Name
Pin Function
1
Input
Resets current sense latch and turns on power MOSFET when taken above
threshold (3.5V typical). Pin 1 requires <1µA to switch.
2
Threshold
Sets current sense trip voltage according to:
2200
V
=
TRIP
R
+1000
TH
where RTH to ground is 3.3k to 20kΩ. Adding capacitor CTH increases the
trip voltage at turn-on to 2V. Use CTH =10µF for a 10ms turn-on time
constant.
3
4
Sense
The sense pin causes the current sense to trip when VSENSE is VTRIP above
VSOURCE. Pin 3 is used in conjunction with a current shunt in the source of
a 3 lead FET or a resistor RS in the sense lead of a current sensing FET.
Source
Reference for the current sense voltage on pin 3 and return for the gate
clamp zener. Connect to the load side of current shunt or kelvin lead of
current sensing FET. Pins 3 and 4 can safely swing to –10V when turning
off inductive loads.
5
6
Ground
Gate
Drives and clamps the gate of the power FET. Pin 6 will be clamped to
approximately –0.7V by an internal diode when turning off inductive loads.
7
8
V+
Supply pin; must be decoupled to isolate from large transients caused by
the power FET drain. 10µF is recommended close to pins 7 and 5.
Fault
Outputs status of protection circuit when pin 1 is high. Fault low indicates
normal operation; fault high indicates current sense tripped.
Pin Configuration
MIC5013
8
7
6
5
1
2
3
4
Input
Fault
Thresh
Sense
Source
V+
Gate
Gnd
MIC5013
2
July 2000
MIC5013
Micrel
Electrical Characteristics (Note 3) Test circuit. TA = –55°C to +125°C, V+ = 15V, all switches open, unless
otherwise specified.
Parameter
Conditions
Min Typical Max
Units
Supply Current, I7
V+ = 32V
VIN = 0V, S4 closed
VIN = VS = 32V
0.1
8
10
20
2
µA
mA
V
Logic Input Voltage, VIN
Logic Input Current, I1
V+ = 4.75V
Adjust VIN for VGATE low
Adjust VIN for VGATE high
Adjust VIN for VGATE high
VIN = 0V
4.5
5.0
–1
V
V+ =15V
V
V+ = 32V
µA
µA
pF
V
VIN = 32V
1
Input Capacitance
Gate Drive, VGATE
Pin 1
5
15
S1, S2 closed,
VS = V+, VIN = 5V
S2 closed, VIN = 5V
V+ = 7V, I6 = 0
13
24
11
11
V+ = 15V, I6 = 100 µA
V+ = 15V, VS = 15V
V+ = 32V, VS = 32V
27
V
Zener Clamp,
12.5
13
15
16
V
VGATE – VSOURCE
V
Gate Turn-on Time, tON
(Note 4)
VIN switched from 0 to 5V; measure time
for VGATE to reach 20V
60
200
µs
Gate Turn-off Time, tOFF
VIN switched from 5 to 0V; measure time
for VGATE to reach 1V
4
10
µs
Threshold Bias Voltage, V2
Current Sense Trip Voltage,
VSENSE – VSOURCE
I2 = 200 µA
1.7
75
2
2.2
135
130
270
260
680
650
V
S2 closed, VIN = 5V,
Increase I3
V+ = 7V,
S4 closed
105
100
210
200
520
500
2.1
mV
mV
mV
mV
mV
mV
V
I2 = 100 µA
V+ = 15V
VS = 4.9V, S4 open
S4 closed
70
150
140
360
350
1.6
I2 = 200 µA
V+ = 32V
VS = 11.8V, S4 open
VS = 0V, S4 open
VS = 25.5V, S4 open
I2 = 500 µA
Peak Current Trip Voltage,
VSENSE – VSOURCE
S3, S4 closed,
V+ = 15V, VIN = 5V
Fault Output Voltage, V8
VIN = 0V, I8 = –100 µA
0.4
1
V
V
VIN = 5V, I8 = 100 µA, current sense tripped
14
14.6
Note 1 Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when
operating the device beyond its specified Operating Ratings.
Note 2 The MIC5010 is ESD sensitive.
Note 3 Minimum and maximum Electrical Characteristics are 100% tested at T = 25°C and T = 85°C, and 100% guaranteed over the entire
A
A
range. Typicals are characterized at 25°C and represent the most likely parametric norm.
Note 4 Test conditions reflect worst case high-side driver performance. Low-side and bootstrapped topologies are significantly faster—see
Applications Information.
July 2000
3
MIC5013
MIC5013
Micrel
Test Circuit
V+
+
1µF
I3
MIC5013
8
7
6
5
1
2
3
4
Input
Fault
V
Thresh
Sense
V+
IN
I8
V GATE
1nF
50Ω
Gate
Source Gnd
S1
500Ω
1W
3.5k
S3
I2
I6
S4
S2
VS
Typical Characteristics
Supply Current
DC Gate Voltage
above Supply
14
12
10
8
12
10
8
6
6
4
4
2
0
2
0
0
3
6
9
12
15
0
5
10 15 20 25 30 35
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
High-side Turn-on Time*
High-side Turn-on Time*
350
300
250
200
150
100
50
3.5
3.0
2.5
2.0
1.5
1.0
0.5
C
GATE
=1 nF
C
GATE
=10 nF
0
0
0
3
6
9
12
15
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
+
+
* Time for gate to reach V + 5V in test circuit with VS = V – 5V (prevents gate clamp from interfering with measurement).
MIC5013
4
July 2000
MIC5013
Micrel
Typical Characteristics (Continued)
Low-side Turn-on Time
for Gate = 5V
Low-side Turn-on Time
for Gate = 10V
1000
3000
1000
300
100
30
C
GATE
=10 nF
300
C
GATE
=10 nF
100
30
10
3
C
GATE
=1 nF
C
GATE
=1 nF
10
1
3
0
3
6
9
12
15
0
3
6
9
12
15
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Turn-on Time
Turn-off Time
2.0
1.75
1.5
50
40
C
GATE
=10 nF
30
20
1.25
1.0
C
=1 nF
12
10
GATE
0.75
0.5
0
0
3
6
9
15
–25
0
25
50 75 100 125
SUPPLY VOLTAGE (V)
DIE TEMPERATURE (°C)
Charge Pump
Output Current
250
200
150
100
50
+
V
=V
GATE
+
V
=V +5V
GATE
+
VS=V –5V
0
0
5
10
15 20 25
30
SUPPLY VOLTAGE (V)
July 2000
5
MIC5013
MIC5013
Micrel
Block Diagram
V+
7
CHARGE
PUMP
Gate
6
500Ω
1
8
Input
Fault
LOGIC
V+
12.5V
CURRENT
SENSE
MIC5013
LATCH
R
Q
+
Sense
3
4
S
I2
–
+
VTRIP
–
1k
V. REG
Source
1k
5
Ground
2
Threshold
Applications Information
When the current sense has tripped, the fault pin 8 will be
highaslongastheinputpin1remainshigh. However, when
the input is low the fault pin will also be low.
Functional Description (refer to block diagram)
The various MIC5013 functions are controlled via a logic
block connected to the input pin 1. When the input is low, all
functions are turned off for low standby current and the gate
of the power MOSFET is also held low through 500Ω to an
N-channel switch. When the input is taken above the turn-
on threshold (3.5V typical), the N-channel switch turns off
and the charge pump is turned on to charge the gate of the
powerFET. Abandgaptypevoltageregulatorisalsoturned
on which biases the current sense circuitry.
Construction Hints
High current pulse circuits demand equipment and assem-
bly techniques that are more stringent than normal low
current lab practices. The following are the sources of
pitfalls most often encountered during prototyping: Sup-
plies: many bench power supplies have poor transient
response. Circuits that are being pulse tested, or those that
operate by pulse-width modulation will produce strange
results when used with a supply that has poor ripple
rejection, or a peaked transient response. Monitor the
power supply voltage that appears at the drain of a high-
sidedriver(orthesupplysideoftheloadinalow-sidedriver)
with an oscilloscope. It is not uncommon to find bench
power supplies in the 1kW class that overshoot or under-
shoot by as much as 50% when pulse loaded. Not only will
theloadcurrentandvoltagemeasurementsbeaffected,but
it is possible to over-stress various components—espe-
cially electrolytic capacitors—with possibly catastrophic
results. A 10µF supply bypass capacitor at the chip is
recommended.
The charge pump incorporates a 100kHz oscillator and on-
chip pump capacitors capable of charging 1nF to 5V above
supply in 60µs typical. The charge pump is capable of
pumping the gate up to over twice the supply voltage. For
this reason, a zener clamp (12.5V typical) is provided
between the gate pin 6 and source pin 4 to prevent exceed-
ing the V rating of the MOSFET at high supplies.
GS
The current sense operates by comparing the sense volt-
age at pin 3 to an offset version of the source voltage at pin
4. Current I2 flowing in threshold pin 2 is mirrored and
returned to the source via a 1kΩ resistor to set the offset, or
tripvoltage. When(V
–V
)exceedsV
, the
SENSE
SOURCE
TRIP
current sense trips and sets the current sense latch to turn
off the power FET. An integrating comparator is used to
reducesensitivitytospikesonpin3.Thelatchisresettoturn
the FET back on by “recycling” the input pin 1 low and then
high again.
Residual Resistances: Resistances in circuit connections
may also cause confusing results. For example, a circuit
may employ a 50mΩ power MOSFET for low drop, but
careless construction techniques could easily add 50 to
100mΩ resistance. Do not use a socket for the MOSFET. If
the MOSFET is a TO-220 type package, make high-current
drain connections to the tab. Wiring losses have a profound
effect on high-current circuits. A floating millivoltmeter can
identify connections that are contributing excess drop un-
der load.
AresistorR frompin2togroundsetsI2,andhenceV
.
TRIP
TH
An additional capacitor C from pin 2 to ground creates a
TH
higher trip voltage at turn-on, which is necessary to prevent
high in-rush current loads such as lamps or capacitors from
false-tripping the current sense.
MIC5013
6
July 2000
MIC5013
Micrel
V
Applications Information (Continued)
LOAD
+
=7 to 15V
V
VTRIP
IL
RS=
MIC5013
8
7
6
5
1
2
3
4
Control Input
Input
Fault
10µF
+
2200
RTH
RTH
=
–1000
Thresh
Sense
V+
V
LOAD
10kΩ
TRIP
Gate
For this example:
=20A (trip current)
Source Gnd
I
IRF540
L
VTRIP = 200mV
RS
10mΩ
IRC 4LPW-5
(International Resistive Company)
Figure 2. Low-Side Driver with
Current Shunt
Circuit Topologies
current comparator monitors RS and trips if I × R exceeds
L
S
The MIC5013 is suited for use in high- or low-side driver
applications with over-current protection for both current-
sensing and standard MOSFETs. In addition, the MIC5013
works well in applications where, for faster switching times,
the supply is bootstrapped from the MOSFET source out-
put. Low voltage, high-side drivers (such as shown in the
Test Circuit) are the slowest; their speed is reflected in the
gate turn-on time specifications. The fastest drivers are the
low-side and bootstrapped high-side types. Load current
switching times are often much faster than the time to full
gate enhancement, depending on the circuit type, the
MOSFET, and the load. Turn-off times are essentially the
V
. R is selected to produce the desired trip voltage.
TRIP
As a guideline, keep V
500mV (R = 3.3kΩ to 20kΩ). Thresholds at the high end
offer the best noise immunity, but also compromise switch
drop (especially in low voltage applications) and power
dissipation.
within the limits of 100mV and
TRIP
TH
The trip current is set higher than the maximum expected
load current—typically twice that value. Trip point accuracy
is a function of resistor tolerances, comparator offset (only
afewmillivolts),andthresholdbiasvoltage(V2).Thevalues
shown in Figure 2 are designed for a trip current of 20
amperes. It is important to ground pin 4 at the current shunt
sameforallcircuits(lessthan10µstoV =1V).Thechoice
GS
R , to eliminate the effects of ground resistance.
of one topology over another is based on a combination of
considerations including speed, voltage, and desired sys-
tem characteristics. Each topology is described in this
S
A key advantage of the low-side topology is that the load
supply is limited only by the MOSFET BVDSS rating.
Clamping may be required to protect the MOSFET drain
terminal from inductive switching transients. The MIC5013
section. Note that I , as used in the design equations, is the
L
load current that just trips the over-current comparator.
Low-SideDriverwithCurrentShunt(Figure2). Theover-
+
V =24V
+
V
R1=
+
1mA
10µF
MIC5013
8
7
6
5
1
2
3
4
Control Input
Input
Fault
R2=100Ω
RTH
Thresh
Sense
V+
20kΩ
100mV+
IL
V
Gate
TRIP
RS
=
Source Gnd
2200
IRF541
RS
–1000
RTH
=
V
TRIP
100Ω
For this example:
R2
18mΩ
IRC 4LPW-5*
IL =10A (trip current)
VTRIP =100mV
R1
24kΩ
*International Resistive Company
LOAD
Figure 3. High-Side Driver
with Current Shunt
July 2000
7
MIC5013
MIC5013
Micrel
Applications Information (Continued)
VLOAD
+
SR VTRIP
=15V
V
RS
=
MIC5013
R IL – VTRIP
8
7
6
5
1
2
3
4
Control Input
Input
Fault
10µF
RTH
Thresh
Sense
2200
V+
+
RTH=
–1000
20kΩ
LOAD
VTRIP
Gate
Source Gnd
IRCZ44
For this example:
(S=2590,
R=11mΩ)
I
L =20A (trip current)
SENSE
V
TRIP =100mV
RS
SOURCE
22Ω
KELVIN
Figure 4. Low-Side Driver with
Current-Sensing MOSFET
supply should be limited to 15V in low-side topologies;
otherwise, a large current will be forced through the gate
clamp zener.
caused by lead and terminal resistances, and simplify
product assembly. 10% tolerance is normally adequate,
and with shunt potentials of 200mV thermocouple effects
are insignificant. Temperature coefficient is important; a
linear, 500 ppm/°C change will contribute as much as 10%
shift in the over-current trip point. Most power resistors
designed for current shunt service drift less than 100 ppm/
°C.
Low-side drivers constructed with the MIC501X family are
also fast; the MOSFET gate is driven to near supply
immediatelywhencommandedON.Typicalcircuitsachieve
10V enhancement in 10µs or less on a 12 to 15V supply.
High-Side Driver with Current Shunt (Figure 3). The
Low-Side Driver with Current Sensing MOSFET (Figure
4). Several manufacturers now supply power MOSFETs in
which a small sampling of the total load current is diverted
to a “sense” pin. One additional pin, called “Kelvin source,”
is included to eliminate the effects of resistance in the
source bond wires. Current-sensing MOSFETs are speci-
fiedwithasensingratio“S”whichdescribestherelationship
between the on-resistance of the sense connection and the
bodyresistance“R”ofthemainsourcepin. Currentsensing
MOSFETseliminatethecurrentshuntrequiredbystandard
MOSFETs.
comparator input pins (source and sense) float with the
current sensing resistor (R ) on top of the load. R1 and R2
S
add a small, additional potential to V
to prevent false-
TRIP
triggering of the over-current shutdown circuit with open or
inductive loads. R1 is sized for a current flow of 1mA, while
R2 contributes a drop of 100mV. The shunt voltage should
be 200 to 500mV at the trip point. The example of Figure 3
gives a 10A trip current when the output is near supply. The
trip point is somewhat reduced when the output is at ground
as the voltage drop across R1 (and therefore R2) is zero.
High-side drivers implemented with MIC5013 drivers are
self-protected against inductive switching transients. Dur-
ing turn-off an inductive load will force the MOSFET source
5V or more below ground, while the driver holds the gate at
ground potential. The MOSFET is forced into conduction,
and it dissipates the energy stored in the load inductance.
TheMIC5013sourceandsensepins(3and4)aredesigned
towithstandthisnegativeexcursionwithoutdamage.Exter-
nal clamp diodes are unnecessary.
The design equations for a low-side driver using a current
sensing MOSFET are shown in Figure 4. “S” is specified on
the MOSFET’s datasheet, and “R” must be measured or
estimated. V
must be less than R × I , or else R will
TRIP
L S
become negative. Substituting a MOSFET with higher on-
resistance, or reducing V fixes this problem. V
=
TRIP
TRIP
100 to 200mV is suggested. Although the load supply is
limited only by MOSFET ratings, the MIC5013 supply
should be limited to 15V to prevent damage to the gate
clamp zener. Output clamping is necessary for inductive
loads.
Current Shunts (R ). Low-valued resistors are necessary
S
for use at R .Values for R range from 5 to 50mΩ, at 2 to
S
S
10W. Worthy of special mention are Kelvin-sensed, “four-
†
“R” is the body resistance of the MOSFET, excluding bond
terminal” units supplied by a number of manufacturers
resistances. R
as specified on MOSFET data sheets
(see next page). Kelvin-sensed resistors eliminate errors
DS(ON)
†
Suppliers of Kelvin-sensed power resistors:
Dale Electronics, Inc., 2064 12th Ave., Columbus, NE 68601. Tel: (402) 564-3131
International Resistive Co., P.O. Box 1860, Boone, NC 28607-1860. Tel: (704) 264-8861
Kelvin, 14724 Ventura Blvd., Ste. 1003, Sherman Oaks, CA 91403-3501. Tel: (818) 990-1192
RCD Components, Inc., 520 E. Industrial Pk. Dr., Manchester, NH 03103. Tel: (603) 669-0054
Ultronix, Inc., P.O. Box 1090, Grand Junction, CO 81502. Tel: (303) 242-0810
MIC5013
8
July 2000
MIC5013
Micrel
7 to 15V
Applications Information (Continued)
1N5817
100nF
12V
1N4001 (2)
+
10µF
MIC5013
MIC5013
Control Input
RTH
+
8
7
6
5
1
2
3
4
Input
Fault
8
7
6
5
1
2
3
4
Control Input
Input
Fault
10µF
Thresh
Sense
V+
Thresh
Sense
V+
RTH2
1kΩ
20kΩ
Gate
RTH1
22kΩ
Gate
Source Gnd
CTH
22µF
Source Gnd
IRCZ44
IRF540
100Ω
R2
RS
18mΩ
43Ω
+
V
R1=
#6014
LOAD
R1
3.9kΩ
1mA
Figure 5. Time-Variable
Trip Threshold
Figure 6. Bootstrapped
High-Side Driver
includes bond resistances. A Kelvin-connected ohmmeter
(using TAB and SOURCE for forcing, and SENSE and
KELVIN for sensing) is the best method of evaluating “R.”
Alternatively, “R” can be estimated for large MOSFETs
hundredmilliseconds.Itisunwisetosettheover-currenttrip
pointto70Atoaccommodatesuchaload.A“resistive”short
that draws less than 70A could destroy the MOSFET by
allowing sustained, excessive dissipation. If the over-cur-
rent trip point is set to less than 70A, the MIC5013 will not
start a cold filament. The solution is to start the lamp with a
hightrippoint,butreducethistoareasonablevalueafterthe
lamp is hot.
(R
≤ 100mΩ)bysimplyhalvingthestatedR
, or
for
DS(ON)
DS(ON)
DS(ON)
by subtracting 20 to 50mΩ from the stated R
smaller MOSFETs.
High-SideDriverwithCurrentSensingMOSFET (Figure
5). Thedesignstartsbydeterminingthevalueof“S”and“R”
for the MOSFET (use the guidelines described for the low-
The MIC5013 over-current shutdown circuit is designed to
handle this situation by varying the trip point with time (see
side version). Let V
= 100mV, and calculate R for a
Figure 5). R
functions in the conventional manner,
TRIP
S
TH1
desired trip current. Next calculate R and R1. The trip
providingacurrentlimitofapproximatelytwicethatrequired
by the lamp. R acts to increase the current limit at turn-
ontoapproximately10timesthesteady-statelampcurrent.
The high initial trip point decays away according to a 20ms
TH
point is somewhat reduced when the output is at ground as
the voltage drop across R1 is zero. No clamping is required
for inductive loads, but may be added to reduce power
dissipation in the MOSFET.
TH2
time constant contributed by C . R
could be eliminated
TH TH2
with C working against the internal 1kΩ resistor, but this
results in a very high over-current threshold. As a rule of
thumb design the over-current circuitry in the conventional
TH
Typical Applications
Start-up into a Dead Short. If the MIC5013 attempts to turn
on a MOSFET when the load is shorted, a very high current
flows. Theover-currentshutdownwillprotecttheMOSFET,
but only after a time delay of 5 to 10µs. The MOSFET must
be capable of handling the overload; consult the device’s
SOA curve. If a short circuit causes the MOSFET to exceed
its 10µs SOA, a small inductance in series with the source
can help limit di/dt to control the peak current during the 5
to 10µs delay.
manner, then add the R
/C network to allow for lamp
TH2 TH
start-up. Let R
= (R
÷10)–1kΩ, and choose a capaci-
TH2
TH1
tor that provides the desired time constant working against
and the internal 1kΩ resistor.
R
TH2
When the MIC5013 is turned off, the threshold pin (2)
appears as an open circuit, and C is discharged through
TH
R
and R
. This is much slower than the turn-on time
TH1
TH2
constant, and it simulates the thermal response of the
filament. If the lamp is pulse-width modulated, the current
When testing short-circuit behavior, use a current probe
rated for both the peak current and the high di/dt.
limit will be reduced by the residual charge left in C
.
TH
The over-current shutdown delay varies with comparator
overdrive, owingtonoisefilteringinthecomparator. Adelay
of up to 100µs can be observed at the threshold of shut-
down. A20%overdrivereducesthedelaytonearminimum.
Modifying Switching Times. Do not add external capaci-
tors to the gate to slow down the switching time. Add a
resistor (1kΩ to 51kΩ) in series with the gate of the MOS-
FET to achieve this result.
Incandescent Lamps. The cold filament of an incandes-
cent lamp exhibits less than one-tenth as much resistance
as when the filament is hot. The initial turn-on current of a
#6014 lamp is about 70A, tapering to 4.4A after a few
Bootstrapped High-Side Driver (Figure 6). The speed of
a high-side driver can be increased to better than 10µs by
bootstrapping the supply off of the MOSFET source. This
topology can be used where the load is pulse-width modu-
July 2000
9
MIC5013
MIC5013
Micrel
Applications Information (Continued)
12V
100kΩ
100kΩ
10kΩ
100kΩ
20kΩ
+
MIC5013
8
7
6
5
1
2
3
4
10µF
100nF
Input
Fault
Thresh
Sense
V+
MPSA05
Gate
Source Gnd
IRFZ40
100Ω
22mΩ
CPSL-3 (Dale)
1N4148
10kΩ
15V
LOAD
33kΩ
33pF
To MIC5013 Input
MPSA05
Figure 7. 10-Ampere
Electronic Circuit Breaker
100kΩ
4N35
lated (100Hz to 20kHz), or where it is energized for only a
short period of time (≤25ms). If the load is left energized for
a long period of time (>25ms), the bootstrap capacitor will
10mA
Control Input
100kΩ
1kΩ
discharge and the MIC5013 supply pin will fall to V+ = V
DD
–1.4. Underthisconditionpins3and4willbeheldaboveV+
and may false trigger the over-current circuit. A larger
capacitor will lengthen the maximum “on” time; 1000µF will
holdthecircuitupfor2.5seconds,butrequiresmorecharge
time when the circuit is turned off. The optional Schottky
barrier diode improves turn-on time on supplies of less than
10V.
Figure 8. Improved
Opto-Isolator Performance
24V
24V
100kΩ
+
ON
CR2943-NA102A
(GE)
MIC5013
10µF
8
7
6
5
1
Input
Fault
2
3
4
Thresh
Sense
OFF
V+
20kΩ
Gate
Source Gnd
IRFP044 (2)
100Ω
5mΩ
LVF-15 (RCD)
330kΩ
15kΩ
LOAD
Figure 9. 50-Ampere
Industrial Switch
MIC5013
10
July 2000
MIC5013
Micrel
Thisapplicationalsoillustrateshowtwo(ormore)MOSFETs
canbeparalleled. Thisreducestheswitchdrop, anddistrib-
utes the switch dissipation into multiple packages.
Applications Information (Continued)
Since the supply current in the “OFF” state is only a small
leakage, the 100nF bypass capacitor tends to remain
chargedforseveralsecondsaftertheMIC5013isturnedoff.
In a PWM application the chip supply is actually much
higher than the system supply, which improves switching
time.
High-VoltageBootstrap(Figure10).AlthoughtheMIC5013
is limited to operation on 7 to 32V supplies, a floating
bootstrap arrangement can be used to build a high-side
switchthatoperatesonmuchhighervoltages.TheMIC5013
and MOSFET are configured as a low-side driver, but the
load is connected in series with ground. The high speed
normally associated with low-side drivers is retained in this
circuit.
ElectronicCircuitBreaker(Figure7).TheMIC5013forms
the basis of a high-performance, fast-acting circuit breaker.
By adding feedback from FAULT to INPUT the breaker can
be made to automatically reset. If an over-current condition
occurs, the circuit breaker shuts off. The breaker tests the
loadevery18msuntiltheshortisremoved,atwhichtimethe
circuit latches ON. No reset button is necessary.
Power for the MIC5013 is supplied by a charge pump. A
20kHz square wave (15Vp-p) drives the pump capacitor
and delivers current to a 100µF storage capacitor. A zener
diode limits the supply to 18V. When the MIC5013 is off,
power is supplied by a diode connected to a 15V supply.
The circuit of Figure 8 is put to good use as a barrier
between low voltage control circuitry and the 90V motor
supply.
Opto-Isolated Interface (Figure 8). Although the MIC5013
has no special input slew rate requirement, the lethargic
transitions provided by an opto-isolator may cause oscilla-
tions on the rise and fall of the output. The circuit shown
accelerates the input transitions from a 4N35 opto-isolator
by adding hysteresis. Opto-isolators are used where the
control circuitry cannot share a common ground with the
MIC5013 and high-current power supply, or where the
control circuitry is located remotely. This implementation is
intrinsically safe; if the control line is severed the MIC5013
will turn OFF.
Half-Bridge Motor Driver (Figure 11). Closed loop control
of motor speed requires a half-bridge driver. This topology
presents an extra challenge since the two output devices
should not cross conduct (shoot-through) when switching.
Cross conduction increases output device power dissipa-
tion and, in the case of the MIC5013, could trip the over-
current comparator. Speed is also important, since PWM
control requires the outputs to switch in the 2 to 20kHz
range.
Fault-Protected Industrial Switch (Figure 9). The most
commonmanualcontrolforindustrialloadsisapushbutton
on/off switch. The “on” button is physically arranged in a
recess so that in a panic situation the “off” button, which
extends out from the control box, is more easily pressed.
This circuit is compatible with control boxes such as the
CR2943 series (GE). The circuit is configured so that if both
switches close simultaneously, the “off” button has prece-
dence.Ifthereisafaultconditionthecircuitwilllatchoff,and
it can be reset by pushing the “ON” button.
The circuit of Figure 11 utilizes fast configurations for both
the top- and bottom-side drivers. Delay networks at each
input provide a 2 to 3µs dead time effectively eliminating
cross conduction. Both the top- and bottom-side drivers are
protected, so the output can be shorted to either rail without
damage.
15V
+
33kΩ
100µF
1N4003 (2)
MIC5013
90V
33pF
8
7
6
5
1
2
3
4
Input
Fault
1N4746
100kΩ
Thresh
Sense
V+
MPSA05
Gate
IRFP250
4N35
6.2kΩ
10mA
Source Gnd
Control Input
100kΩ
10mΩ
KC1000-4T
(Kelvin)
1kΩ
1N4003
100nF
200V
1/4 HP, 90V
5BPB56HAA100
(GE)
M
15Vp-p, 20kHz
Squarewave
Figure 10. High-Voltage
Bootstrapped Driver
July 2000
11
MIC5013
MIC5013
Micrel
as a switch or another high-side driver to give a delay
Applications Information (Continued)
relative to some other event in the system.
The top-side driver is based on the bootstrapped circuit of
Figure 6, and cannot be switched on indefinitely. The
bootstrap capacitor (1µF) relies on being pulled to ground
by the bottom-side output to recharge. This limits the
maximum duty cycle to slightly less than 100%.
Hysteresis has been added to guarantee clean switching at
turn-on. Note that an over-current condition latches the
relay in a safe, OFF condition. Operation is restored by
either cycling power or by momentarily shorting pin 1 to
ground.
Two of these circuits can be connected together to form an
H-bridge. If the H-bridge is used for locked antiphase
control, no special considerations are necessary. In the
case of sign/magnitude control, the “sign” leg of the H-
bridge should be held low (PWM input held low) while the
other leg is driven by the magnitude signal.
Motor Driver with Stall Shutdown (Figure 13). Tachom-
eter feedback can be used to shut down a motor driver
circuit when a stall condition occurs. The control switch is a
3-way type; the “START” position is momentary and forces
the driver ON. When released, the switch returns to the
“RUN” position, and the tachometer’s output is used to hold
the MIC5013 input ON. If the motor slows down, the tach
output is reduced, and the MIC5013 switches OFF. Resis-
tor “R” sets the shutdown threshold. If the output current
exceeds 30A, the MIC5013 shuts down and remains in that
condition until the momentary “RESET” button is pushed.
Control is then returned to the START/RUN/STOP switch.
If current feedback is required for torque control, it is
availableinchoppedformatthebottom-sidedriver's22mΩ
current-sensing resistor.
Time-Delay Relay (Figure 12). The MIC5013 forms the
basis of a simple time-delay relay. As shown, the delay
commenceswhenpowerisapplied,butthe100kΩ/1N4148
couldbeindependentlydrivenfromanexternalsourcesuch
15V
1N5817
100nF
1N4148
1N4001 (2)
MIC5013
8
7
6
5
+
1
2
3
4
Input
Fault
220pF
20kΩ
22kΩ
1µF
Thresh
Sense
V+
Gate
Source Gnd
IRF541
100Ω
22mΩ
CPSL-3
(Dale)
15kΩ
PWM
INPUT
12V,
10A Stalled
M
15V
+
10kΩ
MIC5013
10µF
1
2
3
4
8
7
6
5
Fault
Input
22kΩ
1nF
Thresh
Sense
V+
10kΩ
Gate
2N3904
Source Gnd
IRF541
22mΩ
CPSL-3
(Dale)
Figure 11. Half-Bridge
Motor Driver
MIC5013
12
July 2000
MIC5013
Micrel
Applications Information (Continued)
12V
+
10µF
MIC5013
100kΩ
1N4148
8
1
2
3
4
Input
Fault
7
6
5
Thresh
Sense
V+
20kΩ
Gate
Source Gnd
IRCZ44
SOURCE
KELVIN
+
OUTPUT
(Delay=5s)
100µF
SENSE
10kΩ
43Ω
100Ω
4.3kΩ
Figure 12. Time-Delay Relay
with 30A Over-Current Protection
1N4148
330kΩ
12V
+
RESET
10µF
MIC5013
1
8
7
6
5
Input
Fault
V+
330kΩ
R
2
3
4
Thresh
Sense
330kΩ
20kΩ
Gate
Source Gnd
IRCZ44
SOURCE
SENSE
43Ω
KELVIN
1N4148
4.3kΩ
100nF
M
T
12V
START
RUN
STOP
Figure 13. Motor Stall
Shutdown
July 2000
13
MIC5013
MIC5013
Micrel
Q5. For the second phase Q4 turns off and Q3 turns on,
pushing pin C2 above supply (charge is dumped into the
gate). Q3 also charges C1. On the third phase Q2 turns off
and Q1 turns on, pushing the common point of the two
capacitors above supply. Some of the charge in C1 makes
its way to the gate. The sequence is repeated by turning Q2
and Q4 back on, and Q1 and Q3 off.
Applications Information (Continued)
Gate Control Circuit
When applying the MIC5010, it is helpful to understand the
operation of the gate control circuitry (see Figure 14). The
gate circuitry can be divided into two sections: 1) charge
pump (oscillator, Q1-Q5, and the capacitors) and 2) gate
turn-off switch (Q6).
In a low-side application operating on a 12 to 15V supply,
theMOSFETisfullyenhancedbytheactionofQ5alone.On
supplies of more than approximately 14V, current flows
directly from Q5 through the zener diode to ground. To
prevent excessive current flow, the MIC5010 supply should
be limited to 15V in low-side applications.
When the MIC5010 is in the OFF state, the oscillator is
turned off, thereby disabling the charge pump. Q5 is also
turned off, and Q6 is turned on. Q6 holds the gate pin (G) at
ground potential which effectively turns the external MOS-
FET off.
The action of Q5 makes the MIC5013 operate quickly in
low-side applications. In high-side applications Q5
prechargestheMOSFETgatetosupply, leavingthecharge
pump to carry the gate up to full enhancement 10V above
supply. Bootstrapped high-side drivers are as fast as low-
side drivers since the chip supply is boosted well above the
drain at turn-on.
Q6 is turned off when the MIC5013 is commanded on. Q5
pulls the gate up to supply (through 2 diodes). Next, the
chargepumpbeginssupplyingcurrenttothegate. Thegate
acceptschargeuntilthegate-sourcevoltagereaches12.5V
and is clamped by the zener diode.
A 2-output, three-phase clock switches Q1-Q4, providing a
quasi-tripling action. During the initial phase Q4 and Q2 are
ON. C1 is discharged, and C2 is charged to supply through
+
V
Q3
Q5
Q1
125pF
125pF
COM
C2
C1
C1
C2
G
S
Q2
100 kHz
OSCILLATOR
Q4
500Ω
GATE CLAMP
ZENER
12.5V
Q6
OFF
ON
Figure 14. Gate Control
Circuit Detail
MIC5013
14
July 2000
MIC5013
Micrel
Package Information
PIN 1
DIMENSIONS:
INCH (MM)
0.380 (9.65)
0.370 (9.40)
0.255 (6.48)
0.245 (6.22)
0.135 (3.43)
0.125 (3.18)
0.300 (7.62)
0.013 (0.330)
0.010 (0.254)
0.380 (9.65)
0.320 (8.13)
0.018 (0.57)
0.100 (2.54)
0.130 (3.30)
0.0375 (0.952)
8-Pin Plastic DIP (N)
0.026 (0.65)
MAX)
PIN 1
0.157 (3.99)
0.150 (3.81)
DIMENSIONS:
INCHES (MM)
0.020 (0.51)
0.013 (0.33)
0.050 (1.27)
TYP
45°
0.0098 (0.249)
0.0040 (0.102)
0.010 (0.25)
0.007 (0.18)
0°–8°
0.197 (5.0)
0.189 (4.8)
0.050 (1.27)
0.016 (0.40)
SEATING
PLANE
0.064 (1.63)
0.045 (1.14)
0.244 (6.20)
0.228 (5.79)
8-Pin SOP (M)
July 2000
15
MIC5013
MIC5013
Micrel
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 1998 Micrel Incorporated
MIC5013
16
July 2000
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