Texas Instruments 28xxx manual PWM-Chopper PC Submodule, Purpose of the PWM-Chopper Submodule

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PWM-Chopper (PC) Submodule

2.6PWM-Chopper (PC) Submodule

Figure 2-30illustrates the PWM-chopper (PC) submodule within the ePWM module.

Figure 2-30. PWM-Chopper Submodule

EPWMxSYNCI

EPWMxSYNCO

Time-Base

(TB)

Counter

Compare

(CC)

CTR = PRD

CTR = 0

CTR_Dir

CTR = CMPA

CTR = CMPB

 

 

 

CTR = PRD

Event

 

 

 

CTR = 0

 

 

 

Trigger

Action

 

CTR = CMPA

 

and

Qualifier

 

 

 

 

Interrupt

(AQ)

 

 

CTR = CMPB

 

 

 

CTR_Dir

(ET)

 

 

 

 

 

EPWMxB

 

 

Dead

PWM-

Trip

Band

chopper

Zone

(DB)

(PC)

(TZ)

EPWMxA

 

 

 

CTR = 0

 

PIE

EPWMxTZINT

 

 

 

EPWMxINT

EPWMxSOCA

EPWMxSOCB

EPWMxA

EPWMxB

TZ1 to TZ6

PIE

ADC

GPIO MUX

The PWM-chopper submodule allows a high-frequency carrier signal to modulate the PWM waveform generated by the action-qualifier and dead-band submodules. This capability is important if you need pulse transformer-based gate drivers to control the power switching elements.

2.6.1 Purpose of the PWM-Chopper Submodule

The key functions of the PWM-chopper submodule are:

∙Programmable chopping (carrier) frequency

∙Programmable pulse width of first pulse

∙Programmable duty cycle of second and subsequent pulses

∙Can be fully bypassed if not required

2.6.2Controlling the PWM-Chopper Submodule

The PWM-chopper submodule operation is controlled via the registers in Table 2-15.

Table 2-15. PWM-Chopper Submodule Registers

mnemonic

Address offset

Shadowed

Description

PCCTL

0x001E

No

PWM-chopper Control Register

2.6.3 Operational Highlights for the PWM-Chopper Submodule

Figure 2-31shows the operational details of the PWM-chopper submodule. The carrier clock is derived from SYSCLKOUT. Its frequency and duty cycle are controlled via the CHPFREQ and CHPDUTY bits in the PCCTL register. The one-shot block is a feature that provides a high energy first pulse to ensure hard and fast power switch turn on, while the subsequent pulses sustain pulses, ensuring the power switch remains on. The one-shot width is programmed via the OSHTWTH bits. The PWM-chopper submodule can be fully disabled (bypassed) via the CHPEN bit.

SPRU791D–November 2004–Revised October 2007

ePWM Submodules

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Contents Reference Guide Submit Documentation Feedback Contents Controlling a 3-Phase Interleaved DC/DC Converter List of Figures Event-Trigger Socb Pulse Generator Simplified ePWM Module List of Tables Submit Documentation Feedback Peripheral Guides Related Documentation From Texas InstrumentsData Manuals CPU Users GuidesApplication Reports Tools GuidesTMS320C28x, C28x are trademarks of Texas Instruments TrademarksSubmit Documentation Feedback Introduction Submodule Overview IntroductionMultiple ePWM Modules ∙ Peripheral Bus ∙ PWM output signals EPWMxA and EPWMxB∙ Trip-zone signals TZ1 to TZ6 ∙ ADC start-of-conversion signals EPWMxSOCA and EPWMxSOCBRegister Mapping EPWM Submodules and Critical Internal Signal InterconnectsCounter-Compare Submodule Registers Offset Size NameDescription Time-Base Submodule RegistersEPWM Submodules Submodule Configuration Parameter or Option Submodule Configuration ParametersOverview Tbup Example 2-1. Constant Definitions Used in the Code ExamplesChpenable Purpose of the Time-Base Submodule Time-Base TB SubmoduleTime-Base Submodule Registers Controlling and Monitoring the Time-base SubmoduleRegister ∙ Down-Count Mode Key Time-Base Signals∙ Up-Down-Count Mode ∙ Up-Count Mode∙ Active Register ∙ Time-Base Period Shadow Mode∙ Time-Base Period Immediate Load Mode Time-Base Period Shadow RegisterTime-Base Counter Synchronization Scheme Time-Base Counter SynchronizationEPWM11SYNCO EPWM11SYNCI∙ Software Forced Synchronization Pulse ∙ EPWMxSYNCI Synchronization Input PulseTime-base Counter Modes and Timing Waveforms Phase Locking the Time-Base Clocks of Multiple ePWM ModulesTime-Base Down-Count Mode Waveforms 11. Counter-Compare Submodule Counter-Compare CC SubmoduleRegister Name Address Offset Purpose of the Counter-Compare SubmoduleControlling and Monitoring the Counter-Compare Submodule Counter-Compare Submodule Registers∙ Immediate Load Mode Count Mode Timing WaveformsCounter-Compare Submodule Key Signals ∙ Shadow ModeCTR=CMPB CTR=CMPACTR = Cmpb Purpose of the Action-Qualifier Submodule Action-Qualifier AQ SubmoduleAction-Qualifier Submodule Registers ∙ Toggle Action-Qualifier Submodule Possible Input Events∙ Set High ∙ Clear LowTB Counter equals Actions Action-Qualifier Event Priority Action-Qualifier Event Priority for Up-Down-Count ModeAction-Qualifier Event Priority for Up-Count Mode 10. Action-Qualifier Event Priority for Down-Count ModeWhen using up-count mode to generate an asymmetric PWM Waveforms for Common ConfigurationsUse up-down-count mode to generate a symmetric PWM Use up-down-count mode to generate an asymmetric PWM20. Up-Down-Count Mode Symmetrical Waveform Tbctr Example 2-2. Code Sample for FigureValue EPWMxA EPWMxB Tbclk = Sysclkout Example 2-3. Code Sample for FigureEdgePosA Example 2-4. Code Sample for FigureExample 2-5. Code Sample for Figure Tbctr Example 2-6. Code Sample for FigureEPWMxA EPWMxB Example 2-7. Code Sample for Figure12. Dead-Band Generator Submodule Registers Dead-Band Generator DB SubmodulePurpose of the Dead-Band Submodule Controlling and Monitoring the Dead-Band Submodule∙ Polarity Control ∙ Output Mode ControlOperational Highlights for the Dead-Band Submodule ∙ Input Source Selection13. Classical Dead-Band Operating Modes Mode Description29. Dead-Band Waveforms for Typical Cases 0% Duty 100% FED = Dbfed × Ttbclk RED = Dbred × Ttbclk Dead-Band Delay in μSOperational Highlights for the PWM-Chopper Submodule PWM-Chopper PC SubmodulePurpose of the PWM-Chopper Submodule Controlling the PWM-Chopper Submodule31. PWM-Chopper Submodule Operational Details Waveforms16. Possible Pulse Width Values for Sysclkout = 100 MHz One-Shot PulseOSHTWTHz Period Duty Cycle ControlPurpose of the Trip-Zone Submodule Trip-Zone TZ Submodule∙ Cycle-by-Cycle CBC Controlling and Monitoring the Trip-Zone SubmoduleOperational Highlights for the Trip-Zone Submodule 17. Trip-Zone Submodule RegistersScenario B Example 2-8. Trip-Zone Configurations18. Possible Actions On a Trip Event Scenario aGenerating Trip Event Interrupts 36. Trip-Zone Submodule Mode Control Logic37. Trip-Zone Submodule Interrupt Logic Event-Trigger ET SubmoduleOperational Overview of the Event-Trigger Submodule CTR=CMPB CTRD=CMPB 19. Event-Trigger Submodule Registers41. Event-Trigger Interrupt Generator 42. Event-Trigger Soca Pulse Generator Submit Documentation Feedback Controlling Multiple Buck Converters With Independent Applications to Power TopologiesOverview of Multiple Modules Key Configuration CapabilitiesCTR=0 EPWM1B CTR=CMPB Control of Four Buck Stages. Here FPWM1≠ FPWM2≠ FPWM3≠ FPWM4 Buck Waveforms for -3Note Only three bucks shown here 500 Example 3-1. Configuration for Example in FigureControl of Four Buck Stages. Note FPWM2 = N x FPWM1 Controlling Multiple Buck Converters With Same FrequenciesBuck Waveforms for -5Note FPWM2 = FPWM1 Example 3-2. Code Snippet for Configuration in Figure Control of Two Half-H Bridge Stages FPWM2 = N x FPWM1 Controlling Multiple Half H-Bridge HHB ConvertersHalf-H Bridge Waveforms for -7Note Here FPWM2 = FPWM1 Example 3-3. Code Snippet for Configuration in Figure Controlling Dual 3-Phase Inverters for Motors ACI and PmsmEPWM1A 10 -Phase Inverter Waveforms for -9Only One Inverter Shown Example 3-4. Code Snippet for Configuration in Figure 11. Configuring Two PWM Modules for Phase Control Controlling a 3-Phase Interleaved DC/DC Converter Controlling a 3-Phase Interleaved DC/DC Converter13. Control of a 3-Phase Interleaved DC/DC Converter 14 -Phase Interleaved DC/DC Converter Waveforms for Figure Example 3-5. Code Snippet for Configuration in Figure 15. Controlling a Full-H Bridge Stage FPWM2 = FPWM1 16. ZVS Full-H Bridge Waveforms Example 3-6. Code Snippet for Configuration in Figure Submit Documentation Feedback PWM-Chopper Submodule Control Register Proper Interrupt Initialization ProcedureTrip-Zone Submodule Control and Status Registers Time-Base Counter Register Tbctr Field Descriptions Time-Base Phase Register Tbphs Field DescriptionsTime-Base Submodule Registers Time-Base Period Register Tbprd Field DescriptionsBit Field Value Description Time-Base Control Register Tbctl Field DescriptionsSoftware Forced Synchronization Pulse Time-Base Status Register Tbsts Field Descriptions Counter-Compare Submodule RegistersBit Field Counter-Compare B Register Cmpb Field Descriptions Counter-Compare a Register Cmpa Field DescriptionsBits Name Description Counter-Compare Control Register Cmpctl Field Descriptions Action-Qualifier Submodule RegistersBits Name CBD CBU CAD CAU PRD ZROCBD 10. Action-Qualifier Output B Control Register Aqctlb Rldcsf Rldcsf Otsfb Actsfb Otsfa ActsfaCsfb Csfa Csfb Dead-Band Submodule RegistersInmode Polsel Outmode Inmode Reserved PWM-Chopper Submodule Control Register16. PWM-Chopper Control Register Pcctl Bit Descriptions Name Value DescriptionPWM-Chopper Control Register Pcctl Bit Descriptions Trip-Zone Submodule Control and Status RegistersChpduty CBC6 OSHT6 OSHT5 OSHT4 OSHT3 OSHT2 OSHT1CBC6 CBC5 CBC4 CBC3 CBC2 CBC1 OSHT6OST CBC 18. Trip-Zone Control Register Tzctl Field DescriptionsTZB TZA TZBOST CBC INT 20. Trip-Zone Flag Register Tzflg Field Descriptions21. Trip-Zone Clear Register Tzclr Field Descriptions Event-Trigger Submodule Registers22. Trip-Zone Force Register Tzfrc Field Descriptions 23. Event-Trigger Selection Register Etsel Name Description 24. Event-Trigger Prescale Register Etps Field DescriptionsSocb Soca 24. Event-Trigger Prescale Register Etps Field Descriptions26. Event-Trigger Clear Register Etclr Field Descriptions 25. Event-Trigger Flag Register Etflg Field DescriptionsSocb 27. Event-Trigger Force Register Etfrc Field Descriptions Proper Interrupt Initialization Procedure116 Location Modifications, Additions, and Deletions Table A-1. Changes for Revision DAppendix a Important Notice
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