7

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com

SP332_00_0260

erated from V

V+ will show a decrease in the magnitude

inefficiencies in the design.

The clock rate for the charge pump typically

operates at 15kHz. The external capaci-

tors must be 0.1µF with a 16V breakdown

rating.

Phase 3

— V

of the clock is identical to the first phase

— the charge transferred in C

–5V in the negative terminal of C

is applied to the negative side of capacitor

C

+

is at +5V, the voltage potential

across C

Phase 4

— V

clock connects the negative terminal of C

2

to ground and transfers the generated l0V

across C

Again, simultaneously with this, the positive

side of capacitor C

the negative side is connected to ground,

and the cycle begins again.

+10V

GND

GND

-10V

a) C2+

b) C2-

Figure 7. Charge Pump Waveforms

–5V

–5V

+5V

+

+

+

+

–

–

–

–

Figure 8. Charge Pump Phase 1.

–10V

+

+

+

+

–

–

–

–

Figure 10. Charge Pump Phase 2.

–5V

+5V

–5V

+

+

+

+

–

–

–

–

Figure 9. Charge Pump Phase 3.

+10V

+

+

+

+

–

–

–

–

Figure 11. Charge Pump Phase 4.