Microchip Technology IC PIC MCU PIC18F65J15-I/PT TQFP-64 MCP PIC18F65J15-I/PT Data Sheet
Product codes
PIC18F65J15-I/PT
PIC18F87J10 FAMILY
DS39663F-page 184
© 2009 Microchip Technology Inc.
18.4.4
HALF-BRIDGE MODE
In the Half-Bridge Output mode, two pins are used as
outputs to drive push-pull loads. The PWM output
signal is output on the P1A pin, while the complemen-
tary PWM output signal is output on the P1B pin
(Figure 18-4). This mode can be used for half-bridge
applications, as shown in Figure 18-5, or for full-bridge
applications, where four power switches are being
modulated with two PWM signals.
In Half-Bridge Output mode, the programmable
dead-band delay can be used to prevent shoot-through
current in half-bridge power devices. The value of bits,
P1DC<6:0>, 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 18.4.6
“Programmable Dead-Band Delay” for more details
on dead-band delay operations.
Since the P1A and P1B outputs are multiplexed with
the PORTC<2> and PORTE<6> data latches, the
TRISC<2> and TRISE<6> bits must be cleared to
configure P1A and P1B as outputs.
outputs to drive push-pull loads. The PWM output
signal is output on the P1A pin, while the complemen-
tary PWM output signal is output on the P1B pin
(Figure 18-4). This mode can be used for half-bridge
applications, as shown in Figure 18-5, or for full-bridge
applications, where four power switches are being
modulated with two PWM signals.
In Half-Bridge Output mode, the programmable
dead-band delay can be used to prevent shoot-through
current in half-bridge power devices. The value of bits,
P1DC<6:0>, 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 18.4.6
“Programmable Dead-Band Delay” for more details
on dead-band delay operations.
Since the P1A and P1B outputs are multiplexed with
the PORTC<2> and PORTE<6> data latches, the
TRISC<2> and TRISE<6> bits must be cleared to
configure P1A and P1B as outputs.
FIGURE 18-4:
HALF-BRIDGE PWM
OUTPUT
OUTPUT
FIGURE 18-5:
EXAMPLES OF HALF-BRIDGE OUTPUT MODE APPLICATIONS
Period
Duty Cycle
td
td
(1)
P1A
(2)
P1B
(2)
td = Dead Band Delay
Period
(1)
(1)
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: The output signals are shown as active-high.
PIC18F87J10
P1A
P1B
FET
Driver
FET
Driver
V+
V-
Load
+
V
-
+
V
-
FET
Driver
FET
Driver
V+
V-
Load
FET
Driver
FET
Driver
PIC18F87J10
P1A
P1B
Standard Half-Bridge Circuit (“Push-Pull”)
Half-Bridge Output Driving a Full-Bridge Circuit