SP6660 Datasheet, PDF (17/22 Pages) Sipex Corporation – 200mA Charge Pump Inverter or Doubler

C3
+V_IN
FC
1
D1
D2
V+
8
V_OUT1
CAP+
2
SP6660
7
OSC
C4
GND
C1
3
LV
6
CAP- ₄
5 ^OUT
V_OUT2
C2
V_OUT1 = (2 x V_IN) - V_FD1 - V_FD2
V_OUT2 = -V_IN
where
V_OUT1 = positive doubled output voltage,
V_IN = input voltage,
V_FD1 = forward bias voltage across D1,
V_FD2 = forward bias voltage across D2, and
V_OUT2 = inverted output voltage.
Figure 27. The SP6660 Connected for Negative Voltage Conversion with Positive Supply Multiplication
Circuit for Negative Voltage Conversion
with Positive Supply Multiplication
A designer can use the circuit in Figure 27 to
provide both an inverted output voltage at V_OUT1
and a positive multiple of V_IN at V_OUT2
(subtracting the forward biased voltages of D1
and D2). Capacitor C1 is for the charge pump
and capacitor C2 is for the reservoir function to
generate the inverted output voltage at V .
OUT2
Capacitor C3 is for the charge pump and capacitor
C4 is for the reservoir function to generate the
multiplied positive output voltage at V .
OUT1
Designers should pay special attention to the
possibility of higher source impedances at the
generated supplies due to the finite impedance
of the common charge pump driver.
SP6660DS/11
SP6660 200mA Charge Pump Inverter or Doubler
17
© Copyright 2000 Sipex Corporation