DSPIC30F6010 MICROCHIP [Microchip Technology], DSPIC30F6010 Datasheet - Page 92

• Manufacturer Part Number: DSPIC30F6010
• Description: High-Performance Digital Signal Controllers
• Manufacturer: MICROCHIP [Microchip Technology]

dsPIC30F6010
15.7
Dead time generation may be provided when any of the
PWM I/O pin pairs are operating in the Complementary
Output mode. The PWM outputs use Push-Pull drive
circuits. Due to the inability of the power output devices
to switch instantaneously, some amount of time must
be provided between the turn off event of one PWM
output in a complementary pair and the turn on event of
the other transistor.
The PWM module allows two different dead times to be
programmed. These two dead times may be used in
one of two methods described below to increase user
flexibility:
• The PWM output signals can be optimized for dif-
• The two dead times can be assigned to individual
15.7.1
Each complementary output pair for the PWM module
has a 6-bit down counter that is used to produce the
dead time insertion. As shown in Figure 15-4, each
dead time unit has a rising and falling edge detector
connected to the duty cycle comparison output.
15.7.2
The DTCON2 SFR contains control bits that allow the
dead times to be assigned to each of the complemen-
tary outputs. Table 15-1 summarizes the function of
each dead time selection control bit.
DS70119D-page 90
ferent turn off times in the high side and low side
transistors in a complementary pair of transistors.
The first dead time is inserted between the turn off
event of the lower transistor of the complementary
pair and the turn on event of the upper transistor.
The second dead time is inserted between the
turn off event of the upper transistor and the turn
on event of the lower transistor.
PWM I/O pin pairs. This Operating mode allows
the PWM module to drive different transistor/load
combinations with each complementary PWM I/O
pin pair.
Dead Time Generators
DEAD TIME GENERATORS
DEAD TIME ASSIGNMENT
Preliminary
TABLE 15-1:
15.7.3
The amount of dead time provided by each dead time
unit is selected by specifying the input clock prescaler
value and a 6-bit unsigned value. The amount of dead
time provided by each unit may be set independently.
Four input clock prescaler selections have been pro-
vided to allow a suitable range of dead times, based on
the device operating frequency. The clock prescaler
option may be selected independently for each of the
two dead time values. The dead time clock prescaler
values are selected using the DTAPS<1:0> and
DTBPS<1:0> control bits in the DTCON1 SFR. One of
four clock prescaler options (T
may be selected for each of the dead time values.
After the prescaler values are selected, the dead time
for each unit is adjusted by loading two 6-bit unsigned
values into the DTCON1 SFR.
The dead time unit prescalers are cleared on the fol-
lowing events:
• On a load of the down timer due to a duty cycle
• On a write to the DTCON1 or DTCON2 registers.
• On any device Reset.
DTS1A
DTS1I
DTS2A
DTS2I
DTS3A
DTS3I
DTS4A
DTS4I
comparison edge event.
Note:
Bit
Selects PWM1L/PWM1H active edge dead time.
Selects PWM1L/PWM1H inactive edge
dead time.
Selects PWM2L/PWM2H active edge dead time.
Selects PWM2L/PWM2H inactive edge
dead time.
Selects PWM3L/PWM3H active edge dead time.
Selects PWM3L/PWM3H inactive edge
dead time.
Selects PWM4L/PWM4H active edge dead time.
Selects PWM4L/PWM4H inactive edge
dead time.
DEAD TIME RANGES
The user should not modify the DTCON1
or DTCON2 values while the PWM mod-
ule is operating (PTEN = 1). Unexpected
results may occur.
DEAD TIME SELECTION BITS
 2004 Microchip Technology Inc.
Function
CY
, 2T
CY
, 4T
CY
or 8T
CY
)