MAX1822ESA [MAXIM]
High-Side Power Supply; 高侧电源
| 型号： | MAX1822ESA |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | High-Side Power Supply |
| 文件： | 总10页 (文件大小：174K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1892; Rev 0; 1/01
High-Side Power Supply
_______________General Description
____________________________Features
The MAX1822 high-side supply, using a regulated
charge pump, generates a regulated output voltage
11V greater than the input supply voltage to power
high-side switching and control circuits. The MAX1822
allows low-resistance N-channel MOSFETs (FETs) to be
used in circuits that normally require costly, less effi-
cient P-channel FETs and PNP transistors. The high-
side output also eliminates the need for logic FETs in
+5V and other low-voltage switching circuits.
ꢀ +3.5V to +16.5V Operating Supply Voltage Range
ꢀ Output Voltage Regulated to V
ꢀ 150µA (typ) Quiescent Current
ꢀ Power-Ready Output
+ 11V (typ)
CC
A +3.5V to +16.5V input supply range and a typical qui-
escent current of only 150µA make the MAX1822 ideal
for a wide range of line- and battery-powered switching
and control applications where efficiency is crucial.
Also provided is a logic-level power-ready output (PR)
to indicate when the high-side voltage reaches the
proper level.
The MAX1822 comes in an 8-pin SO package and
requires three inexpensive external capacitors. The
MAX1822 is a pin-for-pin replacement to the MAX622.
Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX1822ESA
-40°C to +85°C
8 SO
________________________Applications
High-Side Power Control with N-Channel FETs
Low-Dropout Voltage Regulators
Power Switching from Low Supply Voltages
H-Switches
Stepper Motor Drivers
Battery-Load Management
Portable Computers
Pin Configuration
Typical Operating Circuit
+3.5V TO +16.5V
TOP VIEW
0.1µF
8
C3
CERAMIC
1
7
6
2
V
CC
C1+
C1-
C1+
C2-
PR
1
2
3
4
8
7
6
5
V
CC
C1
C2
+12.5V TO +27.5V
5
3
V
C1-
C2+
OUT
PR
MAX1822
MAX1822
C2+
C2-
GND
V
OUT
GND
4
SO
________________________________________________________________ Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
High-Side Power Supply
ABSOLUTE MAXIMUM RATINGS
V
V
......................................................................................+17V
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
CC
OUT
....................................................................................+30V
I
...................……………………………………………….25mA
OUT
Continuous Total Power Dissipation (T = +70°C)
A
8-pin SO (derate 5.88mW/°C above +70°C)...............471mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
= +5V, T = T
to T , unless otherwise noted.)
MAX
CC
A
MIN
PARAMETER
Supply Voltage
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
3.5
16.5
V
CC
I
= 0, V = 3.5V,
CC
OUT
11.5
14.5
26.5
8.5
12.5
15.5
27.5
10.5
16.5
17.5
29.5
16.5
18
C1 = C2 = 0.047µF, C3 = 1µF
I
= 0, V = 4.5V, C1 = C2 = 0.047µF,
OUT
CC
C3 = 1µF
I
= 0, V = 16.5V, C1 = C2 = 0.01µF,
OUT
CC
C3 = 1µF (Note 2)
High-Side Voltage (Note 1)
V
V
OUT
I
= 50µA, V = 3.5V,
CC
OUT
C1 = C2 = 0.047µF, C3 = 1µF
I
= 250µA, V = 5V,
OUT
CC
15
C1 = C2 = 0.047µF, C3 = 1µF
I
= 500µA, V = 16.5V,
OUT
CC
26.5
29.5
C1 = C2 = 0.01µF, C3 = 1µF (Note 2)
Power-Ready Threshold
Power-Ready Output High
Power-Ready Output Low
PRT
PR
I
I
I
= 0 (Note 3)
12
13.5
4.3
14.5
5
V
V
V
OUT
= 100µA
3.8
OH
SOURCE
PR
= 1mA
SINK
0.4
OL
C1 = C2 = 0.01µF, C3 = 10µF,
Output Voltage Ripple
Switching Frequency
VR
50
90
mV
I
= 1mA, V
= 16.5V
OUT
OUT
CC
F
O
kHz
I
= 0, V = 5V, C1 = C2 = 0.047µF,
CC
150
500
350
C3 = 1µF, T = +25 C
A
Quiescent Supply Current
IQ
µA
I
= 0, V = 16.5V, C1 = C2 = 0.047µF,
CC
OUT
150
C3 = 1µF, T = +25 C
A
Note 1: High-side voltage measured with respect to ground.
Note 2: For V > +13V on the MAX1822, use C1 = C2 = 0.01µF.
CC
Note 3: Power-Ready Threshold is the voltage with respect to ground at V
when PR switches high (PR = V ).
CC
OUT
2
_______________________________________________________________________________________
High-Side Power Supply
__________________________________________Typical Operating Characteristics
MAX1822
SUPPLY CURRENT
vs. C3 CAPACITOR VALUE
MAX1822
SUPPLY CURRENT
vs. C3 CAPACITOR VALUE
400
350
300
250
200
150
100
50
400
350
300
250
200
150
100
50
V
OUT
= +16.5V
CC
C* = 0.01µF
I
= 0
C* = 0.047µF
C* = 0.033µF
T
A
= +25°C
C1 = C2 = 0.01µF
C* =
0.022µF
V
CC
= +5V, I
= 0
OUT
T
= +25°C
A
C* = 0.1µF
C1 = C2 = C*
1
0.01
0
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
C3 CAPACITOR VALUE (µF)
C3 CAPACITOR VALUE (µF)
MAX1822
MAX1822
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAXIMUM OUTPUT CURRENT
vs. C1 = C2 CAPACITOR VALUE
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
1000
900
800
700
600
500
400
300
200
100
0
I
= 0
V
= +5V
OUT
CC
C3 = 1µF
= +25°C
C3 = 10µF
T = +25°C
A
T
A
C1 = C2 = 0.01µF
NOTE: MAXIMUM I
IS THE LOAD
OUT
CURRENT AT THE POINT
WHERE V
LOSE REGULATION.
C1 = C2 = 0.47µF
BEGINS TO
OUT
2
4
6
8
10 12 14 16 18
(V)
0.1
V
CC
C1 = C2 CAPACITANCE VALUE (µF)
MAX1822
MAX1822
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
OUTPUT VOLTAGE
vs. OUTPUT CURRENT
17
16
15
14
13
12
24
23
22
21
20
19
18
V
= +5V
V
= +12V
CC
CC
C3 = 10µF
C3 = 10µF
T
= +25°C
T
= +25°C
A
A
C1 = C2 = 0.47µF
C1 = C2
0.047µF
C1 = C2
0.01µF
C1 = C2
0.022µF
C1 = C2 = 0.22µF
C1 = C2 = 0.01µF
1
2
3
4
5
6
7
8
9
10
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
(mA)
I
(mA)
I
OUT
OUT
_______________________________________________________________________________________
3
High-Side Power Supply
Typical Operating Characteristics (continued)
MAX1822
OUTPUT VOLTAGE RIPPLE
vs. RESERVOIR CAPACITOR C3
MAX1822
TURN-ON TIME
vs. SUPPLY VOLTAGE
200
180
160
140
120
100
80
10
T
A
= +25°C
I
= 0
OUT
= +25°C
T
A
V
OUT
= +16.5V
= 1mA
CC
I
C1 = C2 = 0.01µF
1
V
OUT
= +5V
CC
I
= 500µA
C1 = C2 = 0.047µF
60
40
20
0
0.1
1
2
3
4
5
6
7
8
9
10
0
5
10
(V)
15
20
RESERVOIR CAPACITOR (µF)
V
CC
Pin Description
PIN
1
NAME
C1+
C2-
FUNCTION
Positive terminal to primary charge-pump capacitor
Negative terminal to secondary charge-pump capacitor
2
3
PR
Power-Ready Output. High when V
Ground
is ≥ V
+ 8.5V with respect to GND.
CC
OUT
4
GND
5
V
High-Side Voltage Out
OUT
6
C2+
C1-
Positive terminal to secondary charge-pump capacitor
Negative terminal to primary charge-pump capacitor
Input Supply
7
8
V
CC
4
_______________________________________________________________________________________
High-Side Power Supply
V
OUT
S8
11V
8.5V
POWER-READY
COMPARATOR
S7
S6
C3
RC OSCILLATOR
+
CONTROL LOGIC
V
INT
C2
OVERVOLTAGE
COMPARATOR
S4
S3
S2
V
CC
C1
PR
PR DRIVER
S1
S5
GND
TWO-STAGE CHARGE PUMP
(SWITCHES SHOWN IN REFRESH MODE)
Figure 1. MAX1822 Block Diagram
V
reaches approximately V
OUT
+ 8.5V. PR also goes
OUT
low if V
CC
Detailed Description
Charge-Pump Operation
The MAX1822 is a multistage charge-pump power sup-
ply. Although the charge pump is capable of multiply-
up to four times, the output is regulated to V
CC
+ 11V by an internal feedback circuit for inputs above
4V. The charge pump typically operates at 90kHz, but
falls below this level during operation, i.e., if
the output is overloaded. The PR high level is V
.
CC
Applications Information
ing V
CC
Quiescent Supply Current
MAX1822 quiescent supply current varies with V
and
CC
with the values of C1, C2, and C3 (Typical Operating
Characteristics). Even with no external load, the device
must still pump to overcome internal losses. Large ratios
between C3 and C1 or C2 require more charge-pump
regulates by pulse skipping. When V
exceeds V
OUT
CC
CC
+ 11V, the oscillator shuts off. As V
+ 11V, the oscillator turns on.
dips below V
OUT
cycles to restore V
current rises fairly rapidly to about 1mA at 4V (Typical
Operating Characteristics). This rise occurs because
. As V
falls below 5V, quiescent
OUT
CC
Power-Ready Output
The Power-Ready Output (PR) signals control circuitry
when the high-side voltage reaches a preset level. This
feature can be used to protect external FET switches
from excess dissipation and damage by preventing them
from turning on, except when adequate gate drive levels
are present. When power is applied, PR remains low until
V
no longer pulse skips to regulate at low input volt-
OUT
ages; the oscillator runs continuously, so supply current
is higher. Figure 2 shows the test circuit for the
MAX1822 quiescent supply current.
_______________________________________________________________________________________
5
High-Side Power Supply
Output Ripple
ripple is typically 50mVp-p with V = +5V, C1
C3
1.0µF
V
OUT
CC
and C2 = 0.047µF, and C3 = 1µF (Typical Operating
Characteristics). Ripple can be reduced by increasing
the ratio between the output storage capacitors C3 and
C1 and C2. This is usually accomplished by increasing
C3 and keeping C1 and C2 in the 0.01µF to 0.047µF
V
SUPPLY
A
8
C4
1
7
6
2
V
5
CC
1000µF
V
OUT
C1+
C1-
LOW ESR
C2
0.047µF
range. For example, if C1 and C2 are 0.047µF (V
CC
V
must not exceed 13V) and C3 is 10µF, output ripple
typically falls to 15mV (Typical Operating Character-
istics).
MAX1822
C2+
C2-
C2
0.047µF
GND
4
Capacitor Selection
Capacitor type is unimportant when selecting capaci-
tors for the MAX1822. However, when V
exceeds
CC
13V, C1 and C2 must be no greater than 0.01µF. Using
larger value capacitors with input voltages above 13V
causes excessive amounts of energy to pass through
Figure 2. MAX1822 Quiescent Supply-Current Test Circuit
6-CHANNEL LOAD SWITCH
+5V
C4
1µF
C3
10µF
8
ALL PULLUP RESISTORS = 1M
ALL TRANSISTORS = 1RF541 (NOTE 2)
TO 1A LOAD
1
7
6
2
V
CC
V
OUT
C1+
C1-
5
C2
0.047µF
MAX1822
C2+
C2-
14
74C906
C2
0.047µF
TO 1A LOAD
GND
4
2
4
1
3
TO 1A LOAD
TO 1A LOAD
TO 1A LOAD
6
8
5
9
SW1
SW2
SW3
SW4
10
12
11
13
SW5
SW6
TO 1A LOAD
ALL CAPACITORS = 1µF
(NOTE 1)
7
NOTE 1: 1µF CAPACITORS SUPPRESS SWITCHING TRANSIENTS, SIZE DEPENDS ON LOAD CURRENTS.
NOTE 2: POWER TRANSISTOR TYPE DEPENDS ON LOAD-CURRENT REQUIREMENTS.
Figure 3. Single MAX1822 Driving Six High-Side Switches
6
_______________________________________________________________________________________
High-Side Power Supply
H-BRIDGE MOTOR CONTROL
+5V
14
V+
IRF541
8
V
CC
C3
10µF
IRF541
4
10
13
1
D1
D2
S2
S4
C1
DC MOTOR
+5V
C1
11
5
V
OUT
0.047µF
7
6
C1-
C2+
+
–
MAX1822
DG303
6
9
IN1
IN2
S3
S1
C2
5
0.047µF
IRF541
IRF541
2
C2-
GND
4
GND
D3
3
D4
12
7
REVERSE
FORWARD
Figure 4. H-Bridge Motor Controller
internal switches during charge-pump cycles. This may
damage the device.
high-side output current from the MAX1822 at a given
supply voltage, calculated as follows:
Output Protection
The MAX1822 is not internally short-circuit protected. In
applications where the output is susceptible to short
circuit, external output short-circuit protection must be
provided. Accomplish this by connecting a resistor
V
x (number of channels)
OUT
R
=
MIN
I
OUT
where V
is the high-side output voltage and I
the output current of the MAX1822.
is
OUT
OUT
between V
and the load to limit output current to
OUT
For example, assuming an output current of 1mA and
six channels, as in Figure 3, the minimum pullup resis-
tor value that will not excessively load the MAX1822 is
about 100kΩ, assuming all six channels are pulled low
at the same time. The value of the pullup resistor also
affects the turn-on time of each FET, and hence the
amount of energy dissipated in the FET during turn-on.
less than 25mA. The resistor value is determined by the
following formula:
V
CC
R
≥
CL
25mA
The rate of rise of V
is limited by the RC time con-
GS
Typical Applications
stant of the pullup resistor and FET gate capacitance;
waste power will be dissipated in the FET equal to
One MAX1822 Drives
Six High-Side Switches
(I
LOAD
)2 x r during the RC time period.
DS
Multiple subsystems or modules can be turned on and
off using a single MAX1822 and an open-drain hex
buffer such as the 74C906 (Figure 3). The drains of all
buffer outputs are pulled through resistors to the
H-Bridge Motor Driver
An H-bridge motor driver is shown in Figure 4. The
motor direction can be controlled by toggling between
IN1 and IN2 of the DG303 analog switch. Each switch
section turns on the appropriate FET pair, which pass-
es current through the motor in the desired direction.
MAX1822’s V
. The pullup resistance depends on
OUT
the number of channels being used with the MAX1822
and power-dissipation limitations. The minimum pullup
resistor value is determined by the number of channels
paralleled on each high-side power supply and the
_______________________________________________________________________________________
7
High-Side Power Supply
4-CHANNEL LOAD SWITCH—NO PULLUP RESISTORS
ALL TRANSISTORS = IRF541 (NOTE 1)
TO LOAD
+3.5V TO +16.5V
C3 10µF
3
8
C4
1µF
COM1
COM2
8
5
16
2
V
OUT
1
V
CC
V+
C1+
TO LOAD
TO LOAD
TO LOAD
C1
N01
N02
N03
N04
NC1
NC2
0.01µF
9
7
6
C1-
C2+
12
MAX1822
MAX333
19
4
13
18
C2
COM3
0.01µF
2
C2-
GND
4
7
14
17
NC3
NC4
COM4
IN4
ALL CAPACITORS = 1µF (NOTE 2)
5
V-
IN1
IN2 IN3
NOTE 1: TRANSISTOR TYPE DEPENDS
1
10
11
20
ON LOAD-CURRENT REQUIREMENTS.
SW1
SW2
SW3
SW4
NOTE 2: 1µF CAPACITORS SUPRESS SWITCHING
TRANSIENTS—VALUE DEPENDS
ON LOAD CURRENT.
Figure 5. MAX1822 Powering a MAX333 Quad Analog Switch, Realizing a 4-Channel Load Switch with No Pullup Resistors
depends on the magnitude of the load change in the
application and can be reduced or eliminated if the
load remains relatively constant. With C6 = 1000µF, the
output transient to a 1A load pulsed at 20Hz is typically
less than 150mV. The regulator is turned on by apply-
4-Channel Load Switch with
No Pullup Resistors
Multiple high-side switches can be driven from a single
MAX1822 high-side power supply with no pullup resis-
tors on the FET gates. In Figure 5, a MAX1822 supplies
high-side voltage to a MAX333 quad analog switch to
control any one of four high-side switches. The FET
gates are normally connected to ground when the
MAX333 logic inputs are low.
ing V
to the Enable/Shutdown input and turned off
BATT
by pulling this input to ground.
The regulator output voltage, V
, is set by the ratio of
OUT
R1 to R2, calculated as follows:
Low-Dropout Regulator
In Figure 6, a MAX1822 high-side power supply powers
an LM10 reference and op-amp combination, providing
sufficient gate drive to turn on the FET. This allows the
regulator to achieve less than 70mV dropout at 1A load
using an IRF541, and just under 20mV for a
SMP60N06.
V
OUT
R2 = R1
−1
0.2
If the application does not require logic shutdown, con-
nect the MAX1822 V
eliminate D2.
pin directly to the battery and
CC
The 200mV reference section is configured for a gain of
25 (e.g., 200mV x 25 = 5V) and connects to the nonin-
verting input of the op amp; the regulator’s output con-
nects directly to the inverting input. The op amp
amplifies the error between its inputs and varies the
gate drive to the FET, regulating the output. Capacitor
C6 reduces transients due to load changes; its size
8
_______________________________________________________________________________________
High-Side Power Supply
C4
0.1µF
DROPOUT VOLTAGE
vs. LOAD CURRENT
225
T
A
= +25°C
200
175
150
125
100
75
C5
0.1µF
C3 10µF
5
8
V
BATT
1
V
CC
V
C1+
OUT
C1
R2
0.01µF
24k
R3
1k
IRF541 IRFZ40
D1
1N914
7
6
MAX1822
C1-
C2+
7
R1
1k
3
3
2
1
PR
8
Q1
6
IRF541
LM10
4
50
C2
0.01µF
SMP60N06
25
2
+5V
C2-
GND
4
0
C6
1000µF
0.1
1
10
LOAD CURRENT (A)
ENABLE/SHUTDOWN
D2
1N914
Figure 6. Ultra-Low Dropout Positive Voltage Regulator with Logic-Controlled Enable/Shutdown.
Chip Information
TRANSISTOR COUNT: 158
_______________________________________________________________________________________
9
High-Side Power Supply
________________________________________________________Package Information
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
相关型号：
MAX1822ESA+T
Switched Capacitor Regulator, 90kHz Switching Freq-Max, PDSO8, 0.150 INCH, SOIC-8
MAXIM
MAX1822ESA-T
Switched Capacitor Regulator, 90kHz Switching Freq-Max, PDSO8, 0.150 INCH, SOIC-8
MAXIM
MAX1823AEUB+
Power Supply Support Circuit, Fixed, 1 Channel, BICMOS, PDSO10, LEAD FREE, MICRO, SOP-10
MAXIM
MAX1823AEUB+T
Power Supply Support Circuit, Fixed, 1 Channel, BICMOS, PDSO10, LEAD FREE, MICRO, SOP-10
MAXIM
MAX1823BEUB+
Power Supply Support Circuit, Fixed, 1 Channel, BICMOS, PDSO10, LEAD FREE, MICRO, SOP-10
MAXIM
©2020 ICPDF网 联系我们和版权申明