PIC18F2410-I/ML Microchip Technology, PIC18F2410-I/ML Datasheet - Page 144

• Manufacturer Part Number: PIC18F2410-I/ML
• Description: IC PIC MCU FLASH 8KX16 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2410-I/ML

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• For Use With: XLT28QFN4 - SOCKET TRANS ICE 28QFN W/CABLEAC164322 - MODULE SOCKET MPLAB PM3 28/44QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

PIC18F2X1X/4X1X
FIGURE 15-7:
15.4.5.1
In the Full-Bridge Output mode, the P1M1 bit in the
CCP1CON register allows user to control the forward/
reverse direction. When the application firmware
changes this direction control bit, the module will
assume the new direction on the next PWM cycle.
Just before the end of the current PWM period, the
modulated outputs (P1B and P1D) are placed in their
inactive state, while the unmodulated outputs (P1A and
P1C) are switched to drive in the opposite direction.
This occurs in a time interval of 4 T
Prescale Value) before the next PWM period begins.
The Timer2 prescaler will be either 1, 4 or 16, depend-
ing on the value of the T2CKPS bit (T2CON<1:0>).
During the interval from the switch of the unmodulated
outputs to the beginning of the next period, the
modulated outputs (P1B and P1D) remain inactive.
This relationship is shown in Figure 15-8.
Note that in the Full-Bridge Output mode, the CCP1
module does not provide any dead-band delay. In
general, since only one output is modulated at all times,
dead-band delay is not required. However, there is a
situation where a dead-band delay might be required.
This situation occurs when both of the following
conditions are true:
1.
2.
DS39636D-page 146
The direction of the PWM output changes when
the duty cycle of the output is at or near 100%.
The turn-off time of the power switch, including
the power device and driver circuit, is greater
than the turn-on time.
PIC18F4X1X
Direction Change in Full-Bridge Mode
P1A
P1B
P1C
P1D
EXAMPLE OF FULL-BRIDGE APPLICATION
OSC
* (Timer2
FET
Driver
FET
Driver
QA
QB
Figure 15-9 shows an example where the PWM
direction changes from forward to reverse at a near
100% duty cycle. At time t1, the outputs P1A and P1D
become inactive, while output P1C becomes active. In
this example, since the turn-off time of the power
devices is longer than the turn-on time, a shoot-through
current may flow through power devices, QC and QD
(see Figure 15-7), for the duration of ‘t’. The same
phenomenon will occur to power devices, QA and QB,
for PWM direction change from reverse to forward.
If changing PWM direction at high duty cycle is required
for an application, one of the following requirements
must be met:
1.
2.
Other options to prevent shoot-through current may
exist.
Reduce PWM for a PWM period before
changing directions.
Use switch drivers that can drive the switches off
faster than they can drive them on.
Load
V+
V-
QC
QD
© 2009 Microchip Technology Inc.
FET
Driver
FET
Driver