TC1221 Datasheet, PDF (4/16 Pages) Microchip Technology – High Frequency Switched Capacitor Voltage Converters with Shutdown in SOT Packages

TC1221/TC1222
3.0 DETAILED DESCRIPTION
The TC1221/TC1222 charge pump converters invert
the voltage applied to the V_IN pin. Conversion consists
of a two-phase operation (Figure 3-1). During the first
phase, switches S2 and S4 are opened and S1 and S3
are closed. During this time, C1 charges to the voltage
on V_IN and load current is supplied from C2. During the
second phase, S2 and S4 are closed, and S1 and S3
are opened. This action connects C1 across C2,
restoring charge to C2.
FIGURE 3-1:
IDEAL SWITCHED
CAPACITOR CHARGE
PUMP
S1
S2
V_IN
C1
TC1221/1222
S3
S4
C2
V_OUT = – (V_IN)
OSC
Phase 1
DS21367B-page 4
 2002 Microchip Technology Inc.