TC660EPA [TELCOM]
100mA CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER; 百毫安充电泵DC- TO- DC电压转换器
| 型号： | TC660EPA |
| 厂家： | 
TELCOM SEMICONDUCTOR, INC |
| 描述： | 100mA CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER |
| 文件： | 总8页 (文件大小：124K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
4
EVALUATION
KIT
AVAILABLE
TC660
100mA CHARGE PUMP DC-TO-DC VOLTAGE CONVERTER
GENERAL DESCRIPTION
FEATURES
The TC660 DC-to-DC voltage converter generates a
negative voltage supply, that can support a 100mA maxi-
mumload, fromapositivevoltageinputof1.5Vto5.5V. Only
two external capacitors are required.
■ Pin Compatible with TC7660
■ High Output Current ..................................... 100mA
■ Converts (+1.5V to 5.5V) to (– 1.5V to – 5.5V)
■ Power Efficiency @100mA......................... 88% typ
■ Low Power Consumption ................200µA @ 5 VIN
■ Low Cost and Easy to Use
— Only Two External Capacitors Required
■ Selectable Oscillator Frequency ....... 10kHz/90kHz
■ ESD Protection ...................................................4kV
Power supply voltage is stored on an undedicated
capacitor then inverted and transferred to an output reser-
voir capacitor. The on-board oscillator normally runs at a
frequency of 10kHz with V+ at 5V. This frequency can be
lowered by the addition of an external capacitor from OSC
(pin 7) to ground, or raised to 90kHz by connecting the
frequency control pin (FC) to V+, in order to optimize capaci-
tor size, quiescent current, and output voltage ripple
frequency. Operation using input voltage between 1.5V and
3.0V is accommodated by grounding the LV input (pin 6).
Operation at higher input voltages (3.0V to 5.5V) is accom-
plished by leaving LV open.
APPLICATIONS
■ Laptop Computers
■ µP Based Controllers
■ Process Instrumentation
■ Automotive Instruments
The TC660 open circuit output voltage is within 0.1% of
the input voltage with the output open-circuited. Power
conversion efficiency is 98% when output load is between
2mA and 5mA.
PIN CONFIGURATION (DIP and SOIC)
ORDERING INFORMATION
+
+
FC
+
1
2
3
4
8
7
6
5
FC
+
1
2
3
4
8
7
6
5
V
V
Part No.
Package
Temp. Range
CAP
CAP
OSC
LV
V
OSC
LV
V
TC660COA
TC660CPA
TC660EOA
TC660EPA
TC7660EV
8-Pin SOIC
0°C to +70°C
0°C to +70°C
TC660COA
TC660EOA
TC660CPA
TC660EPA
GND
GND
8-Pin Plastic DIP
8-Pin SOIC
–
–
CAP
CAP
OUT
OUT
– 40°C to +85°C
– 40°C to +85°C
8-Pin Plastic DIP
Evaluation Kit for
Charge Pump Family
FUNCTIONAL BLOCK DIAGRAM
+
+
V
CAP
8
2
1
FC
VOLTAGE–
LEVEL
TRANSLATOR
7
6
RC
OSCILLATOR
4
÷ 2
–
OSC
LV
CAP
5
V
OUT
INTERNAL
VOLTAGE
REGULATOR
LOGIC
NETWORK
TC660
3
GND
TC660-2 9/10/96
TELCOM SEMICONDUCTOR, INC.
4-5
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
TC660
*Static-sensitive device. Unused devices must be stored in conductive
material. Protect devices from static discharge and static fields. Stresses
above those listed under "Absolute Maximum Ratings" may cause perma-
nent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those
indicated in the operation sections of the specifications is not implied.
Exposuretoabsolutemaximumratingconditionsforextendedperiodsmay
affect device reliability.
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage ........................................................... +6V
LV, FC, OSC Input
Voltage (Note 1) ....................... VOUT – 0.3V to (V+ +0.3V)
Current Into LV (Note 1) ...................... 20 µA for V+ >3.5V
Output Short Duration (VSUPPLY ≤ 5.5V) (Note 3) ..10 Sec
Power Dissipation (Note 2) (TA ≤ 70°C)
SOIC ...............................................................470mW
Plastic DIP ......................................................730mW
Operating Temperature Range
C Suffix .................................................. 0°C to +70°C
E Suffix ............................................. – 40°C to +85°C
Storage Temperature Range ................ – 65°C to +150°C
Lead Temperature (Soldering, 10 sec) ................. +300°C
ELECTRICAL CHARACTERISTICS: Specifications Measured Over Operating Temperature Range With,
V+ = 5V, COSC = Open, C1, C2 = 150µF, FC = Open, Test Circuit
(Figure 1), unless otherwise indicated.
Symbol
Parameter
Test Conditions
Min
Typ
Max
Unit
I+
Supply Current
RL = ∞
FC pin = OPEN or GND
FC pin = V+
—
—
200
1
500
3
µA
mA
V+
Supply Voltage Range
LV = HIGH, RL = 1 kΩ
LV = GND, RL = 1 kΩ
LV = OUT, RL = 1 kΩ (Figure 9)
IOUT = 100mA
3
—
—
5.5
5.5
5.5
10
V
1.5
2.5
—
—
ROUT
IOUT
Output Source Resistance
Output Current
6.5
—
Ω
VOUT < – 4V
100
—
mA
kHz
FOSC
Oscillator Frequency
Pin 7 open; Pin 1 open or GND
Pin 1 = V+
—
—
10
90
—
—
+
+
IOSC
PEFF
Input Current
Pin 1 open
Pin 1 = V+
—
—
1.1
5
—
—
µA
Power Efficiency (Note 4)
RL = 1 kΩ connected between V+ & VOUT
RL = 500Ω connected between VOUT & GND
IL = 100mA to GND
96
92
—
98
96
88
—
—
—
%
VOUT EFF
Voltage Conversion Efficiency
RL = ∞
99
99.9
—
%
NOTES: 1. Connecting any input terminal to voltages greater than V+ or less than GND may cause destructive latch-up. It is recommended that no
inputs from sources operating from external supplies be applied prior to "power up" of the TC660.
2. Derate linearly above 50°C by 5.5 mW/°C.
3. To prevent damaging the device, do not short VOUT to V+.
4. To maximize output voltage and efficiency performance, use low ESR capacitors for C1 and C2.
4-6
TELCOM SEMICONDUCTOR, INC.
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
4
TC660
TYPICAL CHARACTERISTICS
All curves are generated using the test circuit of Figure 1 with V+ = 5V, LV = GND, FC = open, and TA = +25°C, unless
otherwise noted.
Supply Current vs.
Supply Voltage
1)
2)
3)
Supply Current vs.
Oscillator Frequency
Efficiency vs.
Load Current
600
10,000
100
+
V
= 5.5V
500
400
92
84
1000
DOUBLER MODE
LV = OUT
DOUBLER MODE
300
200
100
100
10
1
+
+
V
= 3.5V
V
= 4.5V
76
68
60
INVERTING MODE
LV = OPEN
+
V
= 2.5V
LV = GND
+
V
= 1.5V
60
0
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.01
0.1
1
10
100
0
20
40
80
100
SUPPLY VOLTAGE (V)
OSCILLATOR FREQUENCY (kHz)
LOAD CURRENT (mA)
5)
Output Voltage Drop
vs. Load Current
Output Voltage vs.
Oscillator Frequency
Efficiency vs.
Oscillator Frequency
4)
6)
-5.0
2.0
100
96
I
= 10mA
LOAD
I
= 10mA
LOAD
92
1.6
1.2
-4.5
-4.0
-3.5
-3.0
+
V
= 3.5V
+
88
84
80
I
= 1mA
LOAD
V
= 4.5V
I
= 80mA
+
LOAD
V
= 1.5V
I
=
LOAD
80mA
0.8
0.4
0
76
72
+
V
= 2.5V
68
64
60
I
= 1mA
LOAD
+
V
= 5.5V
80
0
20
40
60
100
0.1 0.2 0.4
1
2
4
10 20 40 100
0.1 0.2 0.4
1
2
4
10 20 40 100
LOAD CURRENT (mA)
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY (kHz)
Output Source Resistance
vs. Temperature
Output Source Resistance
vs. Supply Voltage
Oscillator Frequency
vs. Supply Voltage
7)
8)
9)
12
15
12
16
14
LV GROUNDED
+
V
= 1.5VDC
10
8
LV OPEN
12
10
8
9
6
3
6
+
V
= 3VDC
FC = OPEN, OSC = OPEN
4
2
6
+
V
= 5VDC
60 80 100
0
4
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
-40 -20
0
20
40
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TELCOM SEMICONDUCTOR, INC.
4-7
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
TC660
TYPICAL CHARACTERISTICS (Cont.)
Oscillator Frequency
vs. Temperature
11)
12)
Oscillator Frequency
vs. Temperature
Oscillator Frequency
vs. Supply Voltage
10)
100
100
12
10
LV GROUNDED
80
60
40
80
60
40
20
0
LV OPEN
8
6
4
2
0
+
FC = V , OSC = OPEN
+
FC= OPEN, OSC = OPEN
FC = V , OSC = OPEN
20
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
-40 -20
0
20
40
60
80 100
-20
20
40
60
100
80
-40
0
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
Oscillator Frequency
14)
TC7660 and TC660 Output
13)
vs. External Capacitance
Voltage and Power Efficiency
+
vs. Load Current, V = 5V
-3.0
-3.4
-3.8
-4.2
100
100
TC7660
+
FC = V
92
84
76
68
60
10
1
TC660
TC660
EFF
V
OUT
FC = OPEN
0.1
0.01
-4.6
-5.0
TC7660
40
LOAD CURRENT (mA)
1
2
5
10 20
CAPACITANCE (pF)
100
500 2000 10000
0
60
80
100
2.0
PIN DESCRIPTION
Pin No.
Symbol
Description
1
FC
Internal Oscillator frequency control. f ≈ 10 kHz when FC ≈ OPEN; ≈ 90 kHz when
FC = V+. FC has no effect if OSC is overdriven.
2
3
4
5
6
CAP+
GND
CAP–
VOUT
LV
External capacitor, + terminal
Power-Supply Ground (Inverter) or Positive Input (Doubler)
External capacitor, – terminal
Negative Voltage output (Inverter) or Ground (Doubler)
"Low-Voltage" pin. Connect to GND Pin for inverter operation when VIN < 3V; leave
open or GND above 3V. When overdriving OSC, connect to GND.
7
8
OSC
V+
For external control of internal OSC. Connect ext. C from OSC to GND (close to pkg.)
to reduce frequency of oscillator
Positive Voltage Input (Inverter) or Output (Doubler)
4-8
TELCOM SEMICONDUCTOR, INC.
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
4
TC660
Circuit Description
S
S
1
The TC660 contains all the necessary circuitry to com-
plete a voltage inverter (Figure 1), with the exception of two
externalcapacitors,whichmaybeinexpensive150µFpolar-
ized electrolytic capacitors. Operation is best understood by
considering Figure 2, which shows an idealized voltage
inverter. Capacitor C1 is charged to a voltage V+ for the half
cycle when switches S1 and S3 are closed. (Note: Switches
S2 andS4 areopenduringthishalfcycle.)Duringthesecond
half cycle of operation, switches S2 and S4 are closed, with
S1 and S3 open, thereby shifting capacitor C1 negatively by
V+ volts. Charge is then transferred from C1 to C2, such that
the voltage on C2 is exactly V+, assuming ideal switches and
no load on C2.
2
+
V
C
C
1
2
S
S
3
4
V
= – V
OUT
IN
GND
The four switches in Figure 2 are MOS power switches;
S1 is a P-channel device, and S2, S3 and S4 are N-channel
devices. The main difficulty with this approach is that in
integrating the switches, the substrates of S3 and S4 must
always remain reverse-biased with respect to their sources,
but not so much as to degrade their ON resistances. In
addition, at circuit start-up, and under output short circuit
conditions (VOUT = V+), the output voltage must be sensed
and the substrate bias adjusted accordingly. Failure to
accomplish this would result in high power losses and
possible device latch-up. This problem is eliminated in the
TC660 by a logic network which senses the output voltage
(VOUT) together with the level translators, and switches the
substrates of S3 and S4 to the correct level to maintain
necessary reverse bias.
Figure 2. Idealized Switched Capacitor
Theoretical Power Efficiency
Considerations
In theory, a voltage multiplier can approach 100%
efficiency if certain conditions are met:
(1) The drive circuitry consumes minimal power.
(2) The output switches have extremely low ON
resistance and virtually no offset.
(3) The impedances of the pump and reservoir
capacitors are negligible at the pump frequency.
The TC660 approaches these conditions for negative
voltage multiplication if large values of C1 and C2 are used.
Energy is lost only in the transfer of charge between
capacitors if a change in voltage occurs. The energy lost
is defined by:
To improve low-voltage operation, the “LV” pin should
be connected to GND, disabling the internal regulator. For
supply voltages greater than 3.0V, the LV terminal should
be left open to ensure latch-up-proof operation and prevent
device damage.
2
E = 1/2 C1 (V12 – V2 )
V1 and V2 are the voltages on C1 during the pump and
transfer cycles. If the impedances of C1 and C2 are relatively
high at the pump frequency (refer to Figure 2) compared to
the value of RL, there will be a substantial difference in
voltages V1 and V2. Therefore, it is desirable not only to
make C2 as large as possible to eliminate output voltage
ripple, but also to employ a correspondingly large value for
C1 in order to achieve maximum efficiency of operation.
+
V
I
S
1
2
3
4
8
7
6
5
+
V
(+5V)
+
C
TC660
1
150 µF
R
L
I
L
V
OUT
C
2
150 µF
+
Figure 1. TC660 Test Circuit (Inverter)
TELCOM SEMICONDUCTOR, INC.
4-9
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
TC660
The output characteristics of the circuit in Figure 3 are
those of a nearly ideal voltage source in series with 6.5Ω.
Thus, for a load current of –100mA and a supply voltage of
+5V, the output voltage would be – 4.35V.
Dos and Don'ts
• Do not exceed maximum supply voltages.
• Do not connect the LV terminal to GND for supply
voltages greater than 3.0V.
• Do not short circuit the output to V+ in inverting mode
and for more than 10 sec (a very slow startup!) in
doubler mode.
The dynamic output impedance of the TC660 is due,
primarily, to capacitive reactance of the charge transfer
capacitor (C1). Since this capacitor is connected to the
output for only 1/2 of the cycle, the equation is:
2
XC =
= 0.21Ω,
• When using polarized capacitors in the inverting mode,
the + terminal of C1 must be connected to pin 2 of the
TC660 and the + terminal of C2 must be connected to
GND.
2πf C1
where f = 10 kHz and C1 = 150 µF.
Paralleling Devices
Simple Negative Voltage Converter
Any number of TC660 voltage converters may be paral-
leled to reduce output resistance (Figure 4). The reservoir
capacitor, C2, serves all devices, while each device requires
its own pump capacitor, C1. The resultant output resistance
would be approximately:
Figure 3 shows typical connections to provide a nega-
tive supply where a positive supply is available. A similar
scheme may be employed for supply voltages anywhere in
the operating range of +1.5V to +5.5V, keeping in mind that
pin6(LV)istiedtothesupplynegative(GND)onlyforsupply
voltages below 3.0V.
ROUT (of TC660)
ROUT
=
n (number of devices)
+
V
1
2
3
4
8
7
6
5
V
*
OUT
C
+
1
C
2
150 µF
TC660
150 µF
+
+
+
*
NOTES: 1. V
= –V for 1.5V ≤ V ≤ 5.5V
OUT
Figure 3. Simple Negative Converter
+
V
1
2
3
4
8
7
6
5
1
2
3
4
8
TC660
"1"
R
L
C
7
6
5
1
TC660
C
1
"n"
C
2
+
Figure 4. Paralleling Devices Lowers Output Impedance
4-10
TELCOM SEMICONDUCTOR, INC.
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
4
TC660
+
V
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
+
TC660
"1"
150 µF
+
TC660
"n"
150 µF
V
*
OUT
150 µF
+
150 µF
+
+
+
. V
NOTE:
= –n(V ) for 1.5V ≤ V ≤ 5.5V
*
OUT
Figure 5. Increased Output Voltage by Cascading Devices
clock frequency using TTL logic, the addition of a 10kΩ pull-
up resistor to V+ supply is required. Note that the pump
frequency with external clocking, as with internal clocking,
willbe1/2oftheclockfrequency.Outputtransitionsoccuron
the positive-going edge of the clock.
Cascading Devices
The TC660 may be cascaded as shown (Figure 5) to
produce larger negative multiplication of the initial supply
voltage. However, due to the finite efficiency of each device,
the practical limit is 10 devices for light loads. The output
voltage is defined by:
It is also possible to increase the conversion efficiency
of the TC660 at low load levels by lowering the oscillator
frequency.Thisreducestheswitchinglosses,andisachieved
by connecting an additional capacitor, COSC, as shown in
Figure 7. Lowering the oscillator frequency will cause an
undesirableincreaseintheimpedanceofthepump(C1)and
thereservoir(C2)capacitors.Toovercomethis,increasethe
values of C1 and C2 by the same factor that the frequency
has been reduced. For example, the addition of a 100pF
capacitor between pin 7 (OSC) and GND will lower the
oscillator frequency to 1kHz from its nominal frequency of
10kHz (a multiple of 10), and necessitate a corresponding
increase in the values of C1 and C2.
VOUT = –n (VIN)
where n is an integer representing the number of devices
cascaded. The resulting output resistance would be ap-
proximately the weighted sum of the individual TC660 ROUT
values.
Changing the TC660 Oscillator Frequency
Itmaybedesirableinsomeapplications(duetonoiseor
other considerations) to increase the oscillator frequency.
Pin 1, the FC pin, may be connected to V+ to increase
oscillator frequency to 90kHz from a nominal of 10 kHz for
an input supply voltage of 5.0 volts. The oscillator may also
be synchronized to an external clock as shown in Figure 6
and LV must be grounded when overdriving OSC. In a
situation where the designer has generated the external
Positive Voltage Doubler
+
V
1
2
3
4
8
7
6
5
+
+
V
V
1
2
3
4
8
7
6
5
C
+
OSC
TC660
OSC
C
1
CMOS
GATE
V
+
OUT
TC660
150 µF
C
2
+
V
OUT
150 µF
+
Figure 7. Lowering Oscillator Frequency
Figure 6. External Clocking
TELCOM SEMICONDUCTOR, INC.
4-11
100mA CHARGE PUMP DC-TO-DC
VOLTAGECONVERTER
TC660
+
V
+
V
+
V
= –V
OUT
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
D
1
V
=
C
3
OUT
+
D
+
D
D
2
(2 V ) – (2 V )
1
TC660
F
TC660
+
+
V
=
+
C
C
C
2
OUT
1
+
2
(2 V ) – (2 V )
F
1
+
+
C
2
C
4
Figure 8. Positive Voltage Doubler
Figure 9 shows an improved way of using the TC660 as
a voltage doubler.
In this circuit, C1 is first charged to VIN and C2 is quickly
brought to within a diode drop of VIN (to prevent substrate
reversal) through D. The optional 200 Ω resistor is only to
limit the brief latchup current.
Onthenexthalf-cycle,VIN isinserieswithC1; C2isthen
charged to 2 VIN. D is now reverse-biased and plays no
further part. For VIN < 3V, R may be necessary to ensure
startup.
Figure 10. Combined Negative Converter and Positive Multiplier
Efficient Positive Voltage
Multiplication/Conversion
Since the switches that allow the charge pumping op-
eration are bidirectional, the charge transfer can be per-
formed backward as easily as forward. Figure 11 shows a
TC660 transforming –5V to +5V. The only problem here is
that the internal clock and switch-drive section will not
operate until some positive voltage has been generated. A
diode and resistor shown dotted in Figure 11 can be used to
"force" the internal regulator on.
200
V
IN
D
V
1
2
3
4
8
7
6
5
OUT
= 2 V
IN
C
–
C
TC660
2
V
= –V
1
OUT
R
1
2
3
4
8
7
6
5
+
R = 0.1 – 1MΩ
Figure 9. Improved Voltage Doubler
150 µF
1 MΩ
+
C
1
TC660
150 µF
Combined Negative Voltage Conversion
and Positive Supply Multiplication
–
V
INPUT
Figure 10 combines the functions shown in Figures 3
and 8 to provide negative voltage conversion and positive
voltage multiplication simultaneously. In this instance, ca-
pacitors C1 and C3 perform the pump and reservoir func-
tions, respectively, for the generation of the negative volt-
age, while capacitors C2 and C4 are pump and reservoir,
respectively, for the multiplied positive voltage. There is a
penalty in this configuration in that the source impedances
of the generated supplies will be somewhat higher due to
the finite impedance of the common charge pump driver at
pin 2 of the device.
Figure 11. Positive Voltage Multiplier
4-12
TELCOM SEMICONDUCTOR, INC.
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