PIC18F1XK22 Datasheet, PDF (120/388 Pages) Microchip Technology – 20-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC18F1XK22/LF1XK22
13.4.1 HALF-BRIDGE MODE
In Half-Bridge mode, two pins are used as outputs to
drive push-pull loads. The PWM output signal is output
on the CCP1/P1A pin, while the complementary PWM
output signal is output on the P1B pin (see
Figure 13-6). This mode can be used for Half-Bridge
applications, as shown in Figure 13-7, or for Full-Bridge
applications, where four power switches are being
modulated with two PWM signals.
In Half-Bridge mode, the programmable dead-band delay
can be used to prevent shoot-through current in
Half-Bridge power devices. The value of the PDC<6:0>
bits of the PWM1CON register sets the number of
instruction cycles before the output is driven active. If the
value is greater than the duty cycle, the corresponding
output remains inactive during the entire cycle. See
Section 13.4.6 “Programmable Dead-Band Delay
Mode” for more details of the dead-band delay
operations.
Since the P1A and P1B outputs are multiplexed with
the PORT data latches, the associated TRIS bits must
be cleared to configure P1A and P1B as outputs.
FIGURE 13-6:
EXAMPLE OF
HALF-BRIDGE PWM
OUTPUT
Period
Period
P1A⁽²⁾
Pulse Width
td
td
P1B⁽²⁾
(1)
(1)
(1)
td = Dead-Band Delay
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
FIGURE 13-7:
EXAMPLE OF HALF-BRIDGE APPLICATIONS
Standard Half-Bridge Circuit (“Push-Pull”)
FET
Driver
+
P1A
-
FET
Driver
P1B
Load
+
-
Half-Bridge Output Driving a Full-Bridge Circuit
FET
Driver
P1A
FET
Driver
P1B
V+
Load
FET
Driver
FET
Driver
DS41365D-page 120
Preliminary
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