DSPIC30F2020-30I/SP Microchip Technology Inc., DSPIC30F2020-30I/SP Datasheet - Page 140

• Manufacturer Part Number: DSPIC30F2020-30I/SP
• Description: DSP, 16-Bit, 12KB Flash, 512 RAM, 21 I/O, SDIP-28
• Manufacturer: Microchip Technology Inc.
• Type: DSPr

Specifications of DSPIC30F2020-30I/SP

• A/d Inputs: 8-Channels, 10-Bit
• Comparators: 4
• Cpu Speed: 30 MIPS
• Eeprom Memory: 0 Bytes
• Input Output: 21
• Interface: I2C/SPI/UART
• Ios: 21
• Memory Type: Flash
• Number Of Bits: 16
• Package Type: 28-pin SPDIP
• Programmable Memory: 12K Bytes
• Ram Size: 512 Bytes
• Timers: 3-16-bit, 1-32-bit
• Voltage, Range: 3-5.5
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

dsPIC30F1010/202X
12.34.3 APPLICATION OF PUSH-PULL PWM
Push-Pull PWM mode is typically used in transformer
coupled circuits to ensure that no net DC currents flow
through the transformer. Push-Pull mode ensures that
the same duty cycle PWM pulse is applied to the
transformer windings in alternate directions, as shown
in Figure 12-24.
FIGURE 12-24:
DS70178C-page 138
PWM1H
PWM1L
+V
+V
PWH1H
PWH1L
PWM1H
+
IN
+V
IN
PWM1L
+
IN
PWM1L
PWM1H
Dead Time
MODE
PWH1L
PWH1H
T
ON
Period
APPLICATIONS OF PUSH-
PULL PWM MODE
T1
T1
T
OFF
Dead Time
Half Bridge Converter
Push-Pull Buck Converter
T1
Full Bridge Converter
T
ON
Period
L1
L1
T
Dead Time
L1
OFF
V
OUT
+
V
V
OUT
+
OUT
+
Preliminary
12.34.4 APPLICATION OF MULTI-PHASE PWM
Multi-Phase PWM mode is often used in DC/DC con-
verters that must handle very fast load current tran-
sients and fit into tight spaces. A multi-phase converter
is essentially a parallel array of buck converters that
are operated slightly out of phase of each other, as
shown in Figure 12-25. The multiple phases create an
effective switching speed equal to the sum of the indi-
vidual converters. If a single phase is operating with a
333 KHz PWM frequency, then the effective switching
frequency for the circuit is 1 MHz. This high switching
frequency greatly reduces output capacitor size
requirements and improves load transient response.
FIGURE 12-25:
PWM1H
PWM1L
PWM1H
PWM1L
PWM2H
PWM2L
PWM3H
PWM3L
+
V
IN
MODE
PWM2H
PWM1L
L1
APPLICATIONS OF MULTI-
PHASE PWM MODE
© 2006 Microchip Technology Inc.
PWM3H
PWM1L
L2
Multiphase DC/DC
L3
Converter
V
+
OUT