Microchip Technology AC164133 Data Sheet

Buck/Boost Converter PICtail™ Plus Daughter Board User’s Guide

DS70336A-page 50

• Dead-Time Gain – This parameter produces a correction factor that compensates

for the fact that the feed forward gain term does not account for the energy lost
due to the dead time of the PWM signal (the time when both MOSFETs are off).

• Current-Limit Gain – This parameter limits the cumulative control gain when the

current is approaching its upper limit.

After the modifications have been made to the 16-bit 28-pin Starter Development
Board, as specified in Section 2.4 “Using the Daughter Board with the 16-bit 28-pin
Starter Development Board”, do the following:

• Connect the power supply

• Connect the MPLAB ICD 2

• Connect the Buck/Boost Converter PICtail Plus Daughter Board

• Connect the 9V power supply to the 16-bit 28-pin Starter Development Board as

shown in Figure 2-5

Instructions for programming the dsPIC33FJ16GS502 SMPS device are provided in the
Readme file of the respective software folder. Chapter 4. “Demonstration Program
Operation” also describes how to program the dsPIC33FJ16GS502 device using the
MPLAB ICD 2. Figure 4-1 illustrates the program flow of the demonstration program.

FIGURE 4-1:

SMPS DEMONSTRATION PROGRAM FLOW CHART

Note:

While using the Explorer 16 Development Board with the Daughter Board,
the output voltages Buck1+, Buck2+ and Boost+ can be verified by
measuring at output terminals J4, J5 and J8 respectively.

Initialization Routines:

• Peripherals – ADC, PWM, Timers, GPIO, etc.

• Variables – PID Gain Terms, Data Buffers
• Constants – Desired Voltage, Current Limit, etc.

• Interrupts – ADC, Timers

Idle Loop Functions:

Wait for ADC Interrupt

Soft Start Routine

ADC Interrupt Routines:

• Measure V

OUT

• Calculate PID Gain

• Update PWM Duty Cycle

START

ADC Interrupt

Exit ISR