MC7660 查看數據表（PDF） - ON Semiconductor
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MC7660 Datasheet PDF : 10 Pages
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+
10 mF
V+
1
8
2
7
MC7660
3
6
“1”
4
5
MC7660
+
10 mF
1
8
2
7
MC7660
3
6
“n”
4
5
*NOTE: VOUT = -n V+ for 1.5 V ≤ V+ ≤ 10 V
VOUT*
+ 10 mF
+
10 mF
Figure 6. Increased Output Voltage by Cascading Devices
V+
V+
V+
1
8
2
7
MC7660
3
6
4
5
1 kW
CMOS
GATE
VOUT
+ 10 mF
1
8
2
7
MC7660
3
6
4
5
D1
VOUT =
D2 (2 V+) - (2 VF)
+
C1
+
C2
Figure 7. External Clocking
V+
+
C1
1
8
2
7
MC7660
3
6
4
5
COSC
VOUT
+ C2
Figure 8. Lowering Oscillator Frequency
Positive Voltage Multiplication
The MC7660 may be employed to achieve positive
voltage multiplication using the circuit shown in Figure 9.
In this application, the pump inverter switches of the
MC7660 are used to charge C1 to a voltage level of V+ - VF
(where V+ is the supply voltage and VF is the forward voltage
drop of diode D1). On the transfer cycle, the voltage on C1
plus the supply voltage (V+) is applied through diode D2 to
capacitor C2. The voltage thus created on C2 becomes
(2.0 V+) -(2.0 VF), or twice the supply voltage minus the
combined forward voltage drops of diodes D1 and D2.
The source impedance of the output (VOUT) will depend on
the output current, but for V+ = 5.0 V and an output current
of 10 mA, it will be approximately 60 W.
Figure 9. Positive Voltage Multiplier
Combined Negative Voltage Conversion and Positive
Supply Multiplication
Figure 10 combines the functions shown in Figures 4 and
9 to provide negative voltage conversion and positive
voltage multiplication simultaneously. This approach would
be, for example, suitable for generating +9.0 V and -5.0 V
from an existing +5.0 V supply. In this instance, capacitors
C1 and C3 perform the pump and reservoir functions,
respectively, for the generation of the negative voltage,
while capacitors C2 and C4 are pump and reservoir,
respectively, for the multiplied positive voltage. There is a
penalty in this configuration which combines both
functions, however, 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.
V+
1
8
2
7 D1
MC7660
3
6
VOUT =
-(V + - VF)
+ C3
+
4
C1
5
+
VOUT =
D2 (2 V+) - (2 VF)
C2
+
C4
Figure 10. Combined Negative Converter and
Positive Multiplier
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