TC3682/TC3683/TC3684

DS21556B-page 4

 2002 Microchip Technology Inc.

3.0

DETAILED DESCRIPTION

The TC3682/TC3683/TC3684 inverting charge pumps

perform a -2x multiplication of the voltage applied to

synchronous switching matrices and three external

capacitors. When the shutdown input is held at a logic

low, the device goes into a very low power mode of

operation consuming less than 1

µA of supply current.

Figure 3-1 is a block diagram representation of the

TC3682/TC3683/TC3684 architecture. The first switch-

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 TC3682 synchronously

switches

at

12kHz,

the

TC3683

synchronously

switches at 35kHz, and the TC3684 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 low state, the oscillator

and both switch matrices are powered off placing the

TC3682/TC3683/TC3684 in the shutdown mode.

battery,

the

shutdown

mode

minimizes

power

consumption, which in turn will extend the life of the

battery.

FIGURE 3-1:

TC3682/TC3683/TC3684 ARCHITECTURE

SHDN

ENABLE

ENABLE

ENABLE

+

Switch Matrix

(1st Stage)

Switch Matrix

(2nd Stage)

Oscillator

C1

+

C2

+

+