AC162078 Microchip Technology, AC162078 Datasheet - Page 137

• Manufacturer Part Number: AC162078
• Description: HEADER INTRFC MPLAB ICD2 18F1330
• Manufacturer: Microchip Technology

Specifications of AC162078

• Accessory Type: Transition Header
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICD2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

The actual dead time is calculated from the DTCON
register as follows:
Dead Time = Dead-Time Value/(F
Table 14-3 shows example dead-time ranges as a
function of the input clock prescaler selected and the
device operating frequency.
TABLE 14-3:
 2009 Microchip Technology Inc.
(MHz)
F
OSC
40
40
32
25
25
25
20
20
10
10
10
10
40
40
32
32
32
25
20
20
5
5
5
5
4
4
4
4
MIPS
6.25
6.25
6.25
6.25
1.25
1.25
1.25
1.25
2.5
2.5
2.5
2.5
10
10
10
10
8
8
8
8
5
5
5
5
1
1
1
1
Prescaler
Selection
F
F
F
F
F
F
F
EXAMPLE DEAD-TIME
RANGES
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
F
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
/16
/16
/16
/16
/16
/16
/16
/2
/4
/8
/2
/4
/8
/2
/4
/8
/2
/4
/8
/2
/4
/8
/2
/4
/8
/2
/4
/8
Dead-Time
62.5 ns
100 ns
200 ns
400 ns
125 ns
250 ns
500 ns
160 ns
320 ns
640 ns
100 ns
200 ns
400 ns
800 ns
200 ns
400 ns
800 ns
400 ns
800 ns
1.6 s
1.6 s
3.2 s
0.5 s
50 ns
80 ns
1 s
2 s
4 s
Min
OSC
/Prescaler)
Dead-Time
102.4 s
102.4 s
204.8 s
12.8 s
25.6 s
5.12 s
10.2 s
20.5 s
12.8 s
25.6 s
51.2 s
12.8 s
25.6 s
51.2 s
25.6 s
51.2 s
128 s
256 s
3.2 s
6.4 s
6.4 s
16 s
32 s
41 s
32 s
64 s
Max
4 s
8 s
14.7.4
14.8
Independent PWM mode is used for driving the loads
(as shown in Figure 14-19) that drive one winding of a
switched reluctance motor. A particular PWM output
pair is configured in the Independent Output mode
when the corresponding PMODx bit in the PWMCON0
register is set. No dead-time control is implemented
between the PWM I/O pins when the module is operat-
ing in the Independent PWM mode and both I/O pins
are allowed to be active simultaneously. This mode can
also be used to drive stepper motors.
14.8.1
In the Independent PWM mode, each duty cycle gener-
ator is connected to both PWM output pins in a given
PWM output pair. The odd and the even PWM output
pins are driven with a single PWM duty cycle generator.
PWM1 and PWM0 are driven by the PWM channel
which uses the PDC0 register to set the duty cycle,
PWM3 and PWM2 with PDC1, and PWM5 and PWM4
with PDC2 (see Figure 14-3 and Register 14-3).
Note 1: For small PWM duty cycles, the ratio of
2: Changing
Independent PWM Output
PIC18F1230/1330
DEAD-TIME DISTORTION
DUTY CYCLE ASSIGNMENT IN THE
INDEPENDENT PWM MODE
dead time to the active PWM time may
become large. In this case, the inserted
dead time will introduce distortion into
waveforms produced by the PWM mod-
ule. The user can ensure that dead-time
distortion is minimized by keeping the
PWM duty cycle at least three times
larger than the dead time. A similar effect
occurs for duty cycles at or near 100%.
The maximum duty cycle used in the
application should be chosen such that
the minimum inactive time of the signal is
at least three times larger than the dead
time. If the dead time is greater or equal
to the duty cycle of one of the PWM
output pairs, then that PWM pair will be
inactive for the whole period.
DTCON when the PWM is enabled may
result in an undesirable situation. Disable
the PWM (PTEN = 0) before changing the
dead-time value.
the
dead-time
DS39758D-page 137
values
in