TC2682 Datasheet, PDF (4/10 Pages) Microchip Technology – Inverting Charge Pump Voltage Doublers

TC2682/TC2683/TC2684
3.0 DETAILED DESCRIPTION
The TC2682/TC2683/TC2684 inverting charge pumps
perform a -2x multiplication of the voltage applied to the
V_IN pin. Conversion is performed using two
synchronous switching matrices and three external
capacitors.
Figure 3-1 is a block diagram representation of the
TC2682/TC2683/TC2684 architecture. The first switch-
ing stage inverts the voltage present at V_IN and the
second stage uses the ‘-V_IN’ output generated from the
first stage to produce the ‘-2X’ output function from the
second stage switching matrix.
Each device contains an on-board oscillator that
synchronously controls the operation of the charge
pump switching matrices. The TC2682 synchronously
switches at 12kHz, the TC2683 synchronously
switches at 35kHz, and the TC2684 synchronously
switches at 125kHz. The different oscillator frequencies
for this device family allow the user to trade-off
capacitor size versus supply current. Faster oscillators
can use smaller external capacitors, but will consume
more supply current (see Section 1.0 Electrical
Characteristics).
FIGURE 3-1:
TC2682/TC2683/TC2684 ARCHITECTURE
V_IN
+
C1
-V_IN
Switch Matrix
(1st Stage)
Oscillator
+
C2
Switch Matrix
(2nd Stage)
V_OUT = -2V_IN
C_OUT
+
DS21548B-page 4
 2002 Microchip Technology Inc.