Pulse 280 Specifications download pdf (Page 24)

EPWM1A

in1

out1

Buck

Z CA Z CA Z

pwrr

EPWM1A

Operational Description of HRPWM

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Example 5. #Defines for HRPWM Header Files

//--------------------------------

// HRPWM (High Resolution PWM)

//================================

// HRCNFG

#define HR_Disable 0x0

#define HR_REP 0x1 // Rising Edge position

#define HR_FEP 0x2 // Falling Edge position

#define HR_BEP 0x3 // Both Edge position

#define HR_CMP 0x0 // CMPAHR controlled

#define HR_PHS 0x1 // TBPHSHR controlled

#define HR_CTR_ZERO 0x0 // CTR = Zero event

#define HR_CTR_PRD 0x1 // CTR = Period event

2.5.1 Implementing a Simple Buck Converter

In this example, the PWM requirements are:

• PWM frequency = 1 MHz (i.e., TBPRD = 100 )

• PWM mode = asymmetrical, up-count

• Resolution = 12.7 bits (with a MEP step size of 150 ps)

Figure 8 and Figure 9 show the required PWM waveform. As explained previously, configuration for the

ePWM1 module is almost identical to the normal case except that the appropriate MEP options need to be

enabled/selected.

Figure 8. Simple Buck Controlled Converter Using a Single PWM

Figure 9. PWM Waveform Generated for Simple Buck Controlled Converter

High-Resolution Pulse Width Modulator (HRPWM) SPRU924F– April 2005– Revised October 2011

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Pulse 280 Specifications Page 24