PIC18LF2X_13 Datasheet, PDF (193/560 Pages) Microchip Technology – PIC18(L)F2X/45K50 USB Flash MCU Product Brief

PIC18(L)F2X/4XK22
14.4.1 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 CCPx/PxA pin, while the complementary PWM
output signal is output on the PxB pin (see Figure 14-9).
This mode can be used for half-bridge applications, as
shown in Figure 14-9, 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 PWMxCON 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 14.4.5 “Programmable Dead-Band Delay
Mode” for more details of the dead-band delay
operations.
Since the PxA and PxB outputs are multiplexed with the
PORT data latches, the associated TRIS bits must be
cleared to configure PxA and PxB as outputs.
FIGURE 14-8:
EXAMPLE OF HALF-
BRIDGE PWM OUTPUT
Period
Period
PxA⁽²⁾
Pulse Width
td
td
PxB⁽²⁾
(1)
(1)
(1)
td = Dead-Band Delay
Note 1: At this time, the TMRx register is equal to the
PRx register.
2: Output signals are shown as active-high.
FIGURE 14-9:
EXAMPLE OF HALF-BRIDGE APPLICATIONS
Standard Half-Bridge Circuit (“Push-Pull”)
FET
Driver
+
PxA
-
FET
Driver
PxB
Load
+
-
Half-Bridge Output Driving a Full-Bridge Circuit
FET
Driver
PxA
FET
Driver
PxB
V+
Load
FET
Driver
FET
Driver
 2010-2012 Microchip Technology Inc.
DS41412F-page 193