GS7660IP [VISHAY]
Switched-Capacitor Voltage Converter; 开关电容电压转换器
| 型号： | GS7660IP |
| 厂家： | 
VISHAY |
| 描述： | Switched-Capacitor Voltage Converter |
| 文件： | 总9页 (文件大小：113K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
GS7660
New Product
Vishay
formerly General Semiconductor
Switched-Capacitor Voltage Converter
Description
The GS7660 is a monolithic CMOS switched capacitor
voltage converter, designed to be an improved direct
replacement of the popular ICL7660, MAX1044 and
LTC1044. They perform supply voltage conversions from
positive to negative for an input voltage range of +1.5V to
+6.0V to their negative complements of –1.5V to –6.0V.
The input voltage can also be doubled (VOUT = 2VIN),
halved (VOUT = VIN/2), or multiplied (VOUT = ± n.VIN).
SO-8
8 Pin Dip
Features
• Low output impedance ( typical 35Ω at VIN = 5V )
• Low quiescent current ( typical 36µA at VIN = 5V)
• High power conversion efficiency ( typical 98% )
Contained on the chip are a series Power Supply regula-
tor, Oscillator, control Circuitry and four Power MOS
Switches. The oscillator, when unloaded, oscillates at a
nominal frequency of 10 kHz, with an Input voltage of 5.0V.
This frequency can be lowered by the addition of an external
capacitor to the “Osc” terminal or overdriven by an external
frequency source.
• Simple and accurate voltage conversion from
positive to negative polarities
• Improved latch-up protection
• No external diodes required
An Oscillator “boost” function is available to increase the
oscillator frequency which will optimize performance of
certain parameters. The Lv input can be connected to
ground to improve low voltage operation (VIN ≤ 3V), or left
open for input voltages greater than 3V to reduce power
dissipation.
Applications
• – 5V supply from + 5V logic supply
• EIA/TIA – 232E and EIA/TIA – 562 power supplies
• Portable telephones
The GS7660 provides superior performance over earlier
designs by combining low output impedance and low qui-
escent current with high efficiency and by eliminating diode
voltage drop losses. The only external components
required are two low cost electrolytic capacitors.
• Data acquisition systems
• Personal communications equipment
• Panel meters
• Handheld instruments
Typical Application Circuit
VIN (1.5V to 6V)
1
2
3
5
6
7
Required for
VIN 3V
+
GS7660
10µF
C1
VOUT = --VIN
4
8
10µF
C2
+
Negative Voltage Converter
Document Number 74819
24-May-02
www.vishay.com
1
GS7660
Vishay
formerly General Semiconductor
Ordering Information
Order
Number
Pin Configuration
GS7660x x
Top View
Package Outline
P: Plastic Dip
S: SO-8
1
2
3
4
8
7
6
5
Boost
Cap+
GND
Cap--
V
IN
OSC
LV
Operating Junction
Temperature Range
V
OUT
+
I: –40°C to 125°C
Top View
1
2
3
4
8
V
Boost
IN
OSC
LV
Cap+
GND
Cap--
7
6
5
V
OUT
Test Circuit
IS
VIN
BOOST
VIN
1
8
7
IL
OSC
2
CAP+
GND
External
Oscillator
+
GS7660
COSC
C1
10 µF
RL
LV
3
4
6
5
VOUT
CAP-
VOUT
C2
10µF
+
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2
Document Number 74819
24-May-02
GS7660
Vishay
formerly General Semiconductor
Maximum Ratings Ratings at 25°C ambient temperature unless otherwise specified.
Parameter
Symbol
Value
6.0
Unit
V
Supply Voltage (VIN to GND)
Input Voltage (Pin 1, 6 and 7)
LV Input Current
VIN
VIN
–0.3V ≤ VIN ≤ (VIN, +0.3V)
20
V
LV1
µA
Output Short Circuit Duration
Operating Junction Temperature Range
Storage Temperature Range
Continuous
–40 to +125
–65 to +150
TJ
°C
°C
TS
Continuous Power Dissipation
Plastic Dip (Derate 7.9mW/°C above 70°C)
SO-8 (Derate 6mW/°C above 70°C)
PD
630
480
mW
Note: (1) Stresses beyond those listed above may cause permanent damage to the device. Operating at the levels stated above may affect device reliabllity.
Electrical Characteristics VIN = 5.0V LVPin = open, Oscillator free running, I load = 0mA, TA = –40°C to +125°C unless otherwise noted.
Parameter
Conditions
Min
Typ
36
–
Max
Unit
TA = 25°C
–
70
LV = Open
Supply Current
–
100
–
µA
Pin 1,7, VIN = 3V
RL = 10KΩ, LV Open
RL = 10KΩ, LV Gnd
–
20
3.0
1.5
–
–
6.0
6.0
Supply Voltage(1)
V
TA = 25°C
–
–
35
–
70
110
250
370
–
IL = 20mA, FOSC = 10kHz
LV = Open
Output Resistance
Ω
TA = 25°C
–
–
IL = 3mA, FOSC = 1kHz
VIN = 2V, LV to Gnd
–
–
VIN = 5.0V
–
5.0
–
COSC = 0pF, LV to Gnd
Pin 1 Open
Oscillator Frequency
kHz
VIN = 2.0V
2.0
96
98
–
–
Power Efficiency
RL = 5K, FOSC =10kHz, LV = Open
98
99.9
–
–
%
%
Voltage Conversion Efficiency
LV = Open
TA = 25°C
Pin 1 = 0V
Pin 1 = VIN
–
3.0
20
–
Oscillator Sink or
Source Current
VOSC = 0V or VIN
LV = Open
µA
–
–
VIN = 2.0V
–
1.0
100
mΩ
kΩ
Oscillator Impedance
TA = 25°C
VIN = 5.0V
–
–
Note: (1) The GS7660 can operate with or without an external output diode over the full temperature and voltage range. Eliminating the diode reduces voltage
drop losses.
Document Number 74819
24-May-02
www.vishay.com
3
GS7660
Vishay
formerly General Semiconductor
Ratings and
Characteristic Curves(TA = 25°C unless otherwise noted)
Fig. 2 – Power Efficiency
Fig. 1 – Supply Current
vs. Supply Voltage
vs. Load Current (V = 5V)
IN
100
90
50
Boost = Open
40
Boost = Open
LV = Open
80
70
60
50
LV = Open
30
20
LV = GND
10
0
1
2
3
4
5
6
0
10
20
30
40
50
60
70
Supply Voltage (V)
Load Current (mA)
Fig. 3 – Output Voltage
Fig. 4 – Output Voltage
vs. Load Current (V = 5V)
vs. Load Current (V = 2V)
IN
IN
--2.5
--3.0
--3.5
--4.0
--4.5
--5.0
2
1
Boost = Open
LV = Open
Boost = Open
LV = GND
0
--1
--2
0
10
20
30
40
50
60
70
--40
--20
0
20
40
60
80
100 120
Load Current (mA)
Load Current (mA)
Fig. 5 – Oscillator Frequency
vs. Supply Voltage
Fig. 6 – Oscillator Frequency
vs. Value of C
OSC
35
30
25
20
15
Boost = Vin
60
50
40
30
20
LV = Open
LV = GND
Boost = VIN
10
5
LV = Open
Boost = Open
LV = GND
10
5
0
Boost = Open
1
2
3
4
5
6
10
100
1000
10000
External Capacitor (Pin 7 to GND), COSC (pF)
Supply Voltage, VIN (V)
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4
Document Number 74819
24-May-02
GS7660
Vishay
formerly General Semiconductor
Pin Description
Pin
Name
Function
BOOST
Frequency Boost. Connecting BOOST to VIN increases the oscillator frequency by a factor of five.
When the oscillator is driven externally, BOOST has no effect and should be left open.
1
N.C.
CAP+
GND
CAP–
No Connection
2
3
4
Connection to positive terminal of Charge-Pump Capacitor
Ground. For most applications, the positive terminal of the reservoir capacitor is connected to this pin.
Connection to negative terminal of Charge-Pump Capacitor
Negative Voltage Output. For most applications, the negative terminal of the reservoir capacitor is
connected to this pin.
5
VOUT
6
7
8
LV
OSC
VIN
Low-Voltage Operation. Connect to ground for supply voltages below 3.5V.
Oscillator Control Input. Connecting an external capacitor reduces the oscillator frequency.
Power Supply Positive Voltage Input. (1.5V to 6V). VIN is also the substrate connection.
Detailed Description
The GS7660 is a charge-pump voltage converter. The
basic operations is as follows: Switch pairs S1, S2 and S3,
S4 (Fig.7) are alternately closed and opened at the rate of
the oscillator frequency divided by two.
S1
S3
S2
VIN
C1
During the first half of the cycle, when S1 and S2 are
closed and S3 and S4 are open, bucket capacitor C1 is
charged by input voltage. During the second half of the
cycle, when the switches assume the opposite state,
capacitor C1 is connected in parallel with output capacitor
C2 and any voltage differential causes a transfer of charge
from C1 to C2. This process will continue until the voltage
across C2 equals the –VIN voltage.
C2
S4
V
= -(VIN)
OUT
In normal operation, the output voltage will be less than
–VIN, since the switches have internal resistance and C2 is
being discharged by the load.
Fig. 7 – Ideal Voltage Inverter
Document Number 74819
24-May-02
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5
GS7660
Vishay
formerly General Semiconductor
Design Information
f
Low Voltage (LV) Pin
VIN
V
OUT
Fig. 10 (below) shows a simplified circuit diagram of the
GS7660.
C1
C2
R
LOAD
It shows a voltage regulator between the VIN and Gnd, in
series with the Oscillator.
Grounding the LV pin removes the regulator from this
series path and improves low voltage performance down to
1.5V. For supply voltages less than 3.0V, the LV pin should
be connected to ground and left open for voltages above
3.0V.
Fig. 8 – Switched Capacitor Model
To better understand the theory of operation, a review of
the basic switched capacitor building block is helpful (see
Fig. 8). Referring to Fig. 8 and looking at one full cycle of
operation, the charge being drained by the load is Qavg or
IL x T (T being the time period of one full cycle).
The LV pin can be left grounded over the total range of
Input Voltages. This will improve low voltage operation and
increase oscillator frequency. The disadvantage is
increased quiescent current and reduced efficiency at
higher voltages.
All the charge (∆q) flowing into the output is being delivered
by the input to C1 during only half the cycle. Under steady-
state condition, C1 will charge to the level of the input voltage
(VIN) and discharge to the peak level of the output voltage
VIN
CAP+
pin 2
(VOUT). Therefor the voltage change on C1 is VIN – VOUT
.
pin 8
S2
S1
Qavg = ∆q = C1(Vin –Vout
)
1M
IL x T = C1(Vin –Vout) or IL = f x C1(Vin –Vout) f = 1/T
BOOST
Q
Q
(Vin –Vout
)
1
pin 1
IL =
and REQUIV
=
(See fig. 9)
÷ 2
1
f x C1
OSC
pin 7
f x C1
S3
S4
V
OUT
pin 5
Where f is one-half the oscillator frequency.This resistance
is a major component of the output resistance of switched
capacitor circuits.
GND
pin 3
CAP-
pin 4
LV
pin 6
With C1 = C2 = 10µF and Fosc = 10kHz, this resistance
represents 20Ω.
Fig. 10 – Functional Diagram
Under the same conditions, the typical value in the
“Electrical Characteristics” section of the GS7660 is 35Ω.
R
EQUIV
VIN
V
OUT
1
R
=
EQUIV
f × C1
C2
R
LOAD
Fig. 9 – Equivalent Impedance
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Document Number 74819
24-May-02
GS7660
Vishay
formerly General Semiconductor
Oscillator Frequency Control
For normal operation, the Boost, and Oscillator Pins
should be left open. Connecting the Boost pin to the VIN
supply will increase oscillator frequency by a factor of 5,
resulting in lower Output Impedance, less ripple, smaller
required capacitor values and moves the switching noise
out of the audio band. Lower oscillator frequency reduces
quiescent current.
V
IN (1.5V to 6V)
R1
1N914
IOUT
2VIN
(3.0V to 12V)
1
2
3
4
8
7
6
5
200Ω
+
GS7660
+
C2
10µF
C1
10µF
500kΩ
The oscillator frequency can be further controlled by driving
the oscillator input from an external frequency source or
lowered , by connecting an external capacitor to the oscil-
lator input.
Efficiency, Output Impedance and Output Ripple
The power efficiency of a switched capacitor voltage con-
verter is dependent on the internal losses.
The total power loss is:
VIN
(1.5V to 9.0V)
1
2
3
4
8
+
P outp. P switch P cap.
7
Vd
+
+
∑P loss =
+ P conversion
GS7660
Vd
–
VOUT
2VIN–2VD
=
Res.
Res.
Res.
+
6
–
Required for
V+ < 3.0V
+
+
2
5
I
L
P outp.
=
10µF
10µF
f = f osc/2
f.C1
Res.
P switch P cap.
2
+
= I
(
8 R
+ 4 Esr C1 + Esr C2
)
L
SW
Res.
Res.
P conversion =
Figs. 11a and 11b – Voltage Doubler
1
f
1
2
2–Vout2
)
+
C2
(
V ripple2 – 2 Vout. V ripple)]
Voltage Doubling
C1(
V
in
[
2
Figure 11 shows two methods of voltage doubling. In Fig.
11a , R1 is added to ensure that doubling is not inhibited
by a non-destructive latch-up at start-up.This condition can
occur, since the ground pin (pin 3) is raised above the VIN
pin ( pin 8) during start-up.
f = f osc/2
Vripple
R1 increases output impedance and in higher current
applications where the voltage drop across R1 exceeds a two
diode drop, the doubling circuit of Fig 11b is recommended.
1
f = f osc/2
V ripple = I
(
+ 2 Esr C2
)
L
2. C2 .f
The voltage doubler of Fig. 11a is more accurate at low
load currents since the voltage drop across the diode is not
reflected at the output.
Document Number 74819
24-May-02
www.vishay.com
7
GS7660
Vishay
formerly General Semiconductor
Ultra Precision Voltage Divider
(VIN)
An ultra precision voltage divider is shown below in Fig. 12.
To achieve the 0.002% accuracy, the load current has to be
kept below 100nA. However with a slight loss in accuracy,
the load current can be increased.
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
C1
10µF
C1
10µF
+
GS7660
+
GS7660
VOUT
=
--(VIN)
VIN (3.0V to 12V)
1/4 CD4077
1
2
3
4
8
7
6
5
C2
20µF
+
+
GS7660
C1
10µF
Fig. 14 – Paralleling for Lower Output Resistance
VIN
2
±0.002%
+
C2
10µF
Paralleling For Lower Output Impedance
Required for VIN < 3V
IL ≤ 100nA
Fig. 14 above shows two GS7660s connected in parallel to
achieve a lower output resistance. If the output resistance
is dominated by 1/ f C1, which is normally the case with the
GS7660, increasing C1 offers a greater advantage than
the paralleling of circuits.
Fig. 12 – Ultra Precision Voltage Divider
Battery Splitter
Fig. 13 shows a simple solution to obtain complementary +
and – supplies from a single power supply. The output volt-
ages are + and – half the supply voltage. Good accuracy
requires low load currents.
A disadvantage is the requirement of a floating input supply,
which in the case of a battery is not an issue.
+VB /2 (3.0V)
1
2
3
4
8
7
6
5
+
VB
(6V)
–
Required for VB < 6V
+
GS7660
C1
10µF
–
–VB /2 (–3.0V)
–
C2
10µF
+
Output Common
Fig. 13 – Battery Splitter
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Document Number 74819
24-May-02
GS7660
Vishay
formerly General Semiconductor
SO-8 Case Outline
5.00
4.80
5
4
8
1
7
6
3
4.00
3.80
6.20
5.80
2
Dimensions in millimeters
0.51
0.33
1.27 (typ.)
0.25
0.19
1.75
1.35
0.25
0.10
1.27
0.40
8-Pin Dip Case Outline
10.16
9.01
7.12
6.09
Dimensions in millimeters
8.26
7.62
4.96
2.92
0.36
0.20
0.381
(min.)
3.81
2.92
10.92
(max.)
0.56
0.35
2.54 (Typ.)
Document Number 74819
24-May-02
www.vishay.com
9
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