TC1682 Datasheet, PDF (4/10 Pages) Microchip Technology – Inverting Charge Pump Voltage Doublers with Active High Shutdown

TC1682/TC1683/TC1684
3.0 DETAILED DESCRIPTION
The TC1682/TC1683/TC1684 inverting charge pump
converters 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. When the shutdown input is held at a logic
high, the device goes into a very low power mode of
operation consuming less than 1µA of supply current.
Figure 3-1 is a block diagram representation of the
TC1682/TC1683/TC1684 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 TC1682 synchronously
switches at 12kHz, the TC1683 synchronously
switches at 35kHz, and the TC1684 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).
When the shutdown input is in a high state, the
oscillator and both switch matrices are powered off
placing the TC1682/TC1683/TC1684 in the shutdown
mode. When the V_IN supply input is powered from an
external battery, the shutdown mode minimizes power
consumption, which in turn will extend the life of the
battery.
FIGURE 3-1:
TC1682/TC1683/TC1684 ARCHITECTURE
V_IN
+
C1
-V_IN
Switch Matrix
(1st Stage)
Oscillator
ENABLE
ENABLE
SHDN
+
C2
Switch Matrix
(2nd Stage)
ENABLE
V_OUT = -2V_IN
C_OUT
+
DS21537B-page 4
 2002 Microchip Technology Inc.