SLUSB72D March   2013  – April 2021 UCD3138064


  1. Features
  2. Applications
  3. Description
  4. Functional Block Diagram
  5. Revision History
  6. Device Options
    1. 6.1 Device Comparison Table
    2. 6.2 Product Selection Matrix
  7. Pin Configuration and Functions
    1. 7.1 Pin Diagrams
    2. 7.2 Pin Functions
  8. Specifications
    1. 8.1  Absolute Maximum Ratings (1)
    2. 8.2  Handling Ratings
    3. 8.3  Recommended Operating Conditions
    4. 8.4  Thermal Information
    5. 8.5  Electrical Characteristics
    6. 8.6  Timing Characteristics
    7. 8.7  PMBus/SMBus/I2C Timing
    8. 8.8  Power On Reset (POR) / Brown Out Reset (BOR)
    9. 8.9  Typical Clock Gating Power Savings
    10. 8.10 Typical Characteristics
  9. Detailed Description
    1. 9.1 Overview
      1. 9.1.1 ARM Processor
      2. 9.1.2 Memory
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  System Module
        1. Address Decoder (DEC)
        2. Memory Management Controller (MMC)
        3. System Management (SYS)
        4. Central Interrupt Module (CIM)
      2. 9.3.2  Peripherals
        1. Digital Power Peripherals
          1. Front End
          2. DPWM Module
          3. DPWM Events
          4. High Resolution DPWM
          5. Over Sampling
          6. DPWM Interrupt Generation
          7. DPWM Interrupt Scaling/Range
      3. 9.3.3  Automatic Mode Switching
        1. Phase Shifted Full Bridge Example
        2. LLC Example
        3. Mechanism For Automatic Mode Switching
      4. 9.3.4  DPWMC, Edge Generation, Intramux
      5. 9.3.5  Filter
        1. Loop Multiplexer
        2. Fault Multiplexer
      6. 9.3.6  Communication Ports
        1. SCI (UART) Serial Communication Interface
        2. PMBUS/I2C
        3. SPI
      7. 9.3.7  Real Time Clock
      8. 9.3.8  Timers
        1. 24-Bit Timer
        2. 16-Bit PWM Timers
        3. Watchdog Timer
      9. 9.3.9  General Purpose ADC12
      10. 9.3.10 Miscellaneous Analog
      11. 9.3.11 Brownout
      12. 9.3.12 Global I/O
      13. 9.3.13 Temperature Sensor Control
      14. 9.3.14 I/O Mux Control
      15. 9.3.15 Current Sharing Control
      16. 9.3.16 Temperature Reference
    4. 9.4 Device Functional Modes
      1. 9.4.1 DPWM Modes Of Operation
        1. Normal Mode
        2. Phase Shifting
        3. DPWM Multiple Output Mode
        4. DPWM Resonant Mode
      2. 9.4.2 Triangular Mode
      3. 9.4.3 Leading Edge Mode
    5. 9.5 Memory
      1. 9.5.1 Register Maps
        1. CPU Memory Map and Interrupts
          1. Memory Map (After Reset Operation)
          2. Memory Map (Normal Operation)
          3. Memory Map (System and Peripherals Blocks)
        2. Boot ROM
        3. Customer Boot Program
        4. Flash Management
        5. Synchronous Rectifier MOSFET Ramp and IDE Calculation
  10. 10Applications and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. PCMC (Peak Current Mode Control) PSFB (Phase Shifted Full Bridge) Hardware Configuration Overview
        2. DPWM Initialization for PSFB
          1. DPWM Synchronization
        3. Fixed Signals to Bridge
        4. Dynamic Signals to Bridge
        5. System Initialization for PCM
          1. Use of Front Ends and Filters in PSFB
          2. Peak Current Detection
          3. Peak Current Mode (PCM)
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Introduction To Power Supply and Layout Recommendations
    2. 11.2 3.3-V Supply Pins
    3. 11.3 Recommendation for V33 Ramp up Slew Rate for UCD3138 and UCD3138064
    4. 11.4 Recommendation for RC Time Constant of RESET Pin for UCD3138 and UCD3138064
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 EMI and EMC Mitigation Guidelines
      2. 12.1.2 BP18 Pin
      3. 12.1.3 Additional Bias Guidelines
      4. 12.1.4 UART Communication Port
    2. 12.2 Layout Example
      1. 12.2.1 UCD3138 and UCD3138064 40 Pin
      2. 12.2.2 UCD3138 and UCD3138064 64 Pin
  13. 13Device and Documentation Support
    1. 13.1 Device Support
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
Peak Current Detection

Peak current detection involves all the major modules of the DPPs, the Front End, Filter, Loop Mux, Fault Mux and the DPWMs. A drawing of the major elements is shown in Figure 10-8.

GUID-FA602A9D-4E15-46CB-A9CF-A1B6B3341710-low.gifFigure 10-8 Peak Current Detection Function

All signals without arrows flow from left to right. The voltage loop is used to select a peak current level. This level is fed to the Ramp module to generate a compensation ramp. The compensation ramp is compared to the primary current by the PCMC comparator in the Front End. When the ramp value is greater than the primary current, the APCMC signal is sent to the DPWM, causing the events described in the previous sections.

The DPWM frame start and output pin signals can be used to trigger the Ramp Module. In this case, unlike in the case of other ramp module functions, each DPWM frame triggers the start of the ramp. The ramp steps every 32 ns.

The Filter is configured normally, there is no real difference for PCMC. The PCM_FILTER_SEL bits in the LoopMux.PCMCTRL register are used to select which filter is connected to the ramp module:

LoopMuxRegs.PCMCTRL.bit.PCM_FILTER_SEL =0; //select filter0

With Firmware Constant Power/Constant current, Filter 1 and Front End 1 are used as a current control loop, with the EADCDAC set to high current. If the voltage loop value becomes higher than the current loop value, then Filter 1 is used to control the PCM ramp start value:

//select filter1 for slope compensation source

In the ramp module, there are 2 bitfields in the RAMPCTRL register which must be configured. The PCM_START_SEL must be set to a 1 to enable the Filter to be used as a ramp start source. The RAMP_EN bit must be set, of course.

The DAC_STEP register sets the slope of the compensation ramp. The DAC value is in volts, of course, so it is necessary to calculate the slope after the current to voltage conversion. Here is the formula for converting from millivolts per microsecond to DACSTEP.

m = compensation slope in millivolts per microsecond

ACSTEP = 335.5 × M

In C, this can be written:

#define COMPENSATION_SLOPE 150 //compensation slope in millivolts per microsecond
//value in DACSTEP for desired compensation slope

It may also be necessary to set a ramp ending value in the RAMPDACEND register.

In addition, it is necessary to set the D2S_COMP_EN bit in the EADCCTRL register. This is for enabling the differential to single ended comparator function. The front end diagram leaves it out for simplicity, but the connection between the DAC and the EADC amplifier is actually differential. The PCMC comparator, however, is single ended. So a conversion is necessary as shown in Figure 10-9.

GUID-CB307E93-0B01-41BA-9664-DE60354D5699-low.gifFigure 10-9 Differential to Single-Ended Comparator Function

The EADC_MODE bit in EADCCTRL should be set to a 5 for peak current mode.

The peak current detection signal next goes to the Loop Mux. The Fault Mux has only 1 APCM input, but there are 3 front ends. So the PCM_FE_SEL bits in APCMCTRL must be used to select which front end is used:

LoopMuxRegs.APCMCTRL.bit.PCM_FE_SEL = 2; // use FE2 for PCM */

The PCM_EN bit must also be set.

LoopMuxRegs.APCMCTRL.bit.PCM_EN = 1; // Enable PCM

Next the Fault Mux is used to enable the APCM bit to the CLIM/CBC signal to the DPWM. There are 4 DPWMxCLIM registers, one for each DPWM. The ANALOG_PCM_EN bit must be set in each one to connect the PCM detection signal to the CLIM/CBC signal on each DPWM. For the latest configuration information on all of these bits, consult the appropriate EVM firmware. To avoid errors, it is best to configure your hardware design using the same DPWMs, filters, and front ends for the same functions as the EVM.

DPWM timing is used to trigger the start of the ramp. This is selected by the FECTRLxMUX registers in the Loop Mux. DPWMx_FRAME_SYNC_EN bits, when set, cause the ramp to be triggered at the start of the DPWM period.