DLPS039G December   2015  – July 2024 TPS99000-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics—Transimpedance Amplifier Parameters
    6. 5.6  Electrical Characteristics—Digital to Analog Converters
    7. 5.7  Electrical Characteristics—Analog to Digital Converter
    8. 5.8  Electrical Characteristics—FET Gate Drivers
    9. 5.9  Electrical Characteristics—Photo Comparator
    10. 5.10 Electrical Characteristics—Voltage Regulators
    11. 5.11 Electrical Characteristics—Temperature and Voltage Monitors
    12. 5.12 Electrical Characteristics—Current Consumption
    13. 5.13 Power-Up Timing Requirements
    14. 5.14 Power-Down Timing Requirements
    15. 5.15 Timing Requirements—Sequencer Clock
    16. 5.16 Timing Requirements—Host and Diagnostic Port SPI Interface
    17. 5.17 Timing Requirements—ADC Interface
    18. 5.18 Switching Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Illumination Control
        1. 6.3.1.1 Illumination System High Dynamic Range Dimming Overview
        2. 6.3.1.2 Illumination Control Loop
        3. 6.3.1.3 Continuous Mode Operation
          1. 6.3.1.3.1 Output Capacitance in Continuous Mode
          2. 6.3.1.3.2 Continuous Mode Driver Distortion and Blanking Current
          3. 6.3.1.3.3 Continuous Mode S_EN2 Dissipative Load Shunt Options
          4. 6.3.1.3.4 Continuous Mode Constant OFF Time
          5. 6.3.1.3.5 Continuous Mode Current Limit
        4. 6.3.1.4 Discontinuous Mode Operation
          1. 6.3.1.4.1 Discontinuous Mode Pulse Width Limit
          2. 6.3.1.4.2 COMPOUT_LOW Timer in Discontinuous Operation
          3. 6.3.1.4.3 Dimming Within Discontinuous Operation Range
          4. 6.3.1.4.4 Multiple Pulse Heights to Increase Bit Depth
          5. 6.3.1.4.5 TIA Gain Adjustment
          6. 6.3.1.4.6 Current Limit in Discontinuous Mode
          7. 6.3.1.4.7 CMODE Big Cap Mode in Discontinuous Operation
      2. 6.3.2 Over-Brightness Detection
        1. 6.3.2.1 Photo Feedback Monitor BIST
        2. 6.3.2.2 Excessive Brightness BIST
      3. 6.3.3 Analog to Digital Converter
        1. 6.3.3.1 Analog to Digital Converter Input Table
      4. 6.3.4 Power Sequencing and Monitoring
        1. 6.3.4.1 Power Monitoring
      5. 6.3.5 DMD Mirror Voltage Regulator
      6. 6.3.6 Low Dropout Regulators
      7. 6.3.7 System Monitoring Features
        1. 6.3.7.1 Windowed Watchdog Circuits
        2. 6.3.7.2 Die Temperature Monitors
        3. 6.3.7.3 External Clock Ratio Monitor
      8. 6.3.8 Communication Ports
        1. 6.3.8.1 Serial Peripheral Interface (SPI)
    4. 6.4 Device Functional Modes
      1. 6.4.1 OFF
      2. 6.4.2 STANDBY
      3. 6.4.3 POWERING_DMD
      4. 6.4.4 DISPLAY_RDY
      5. 6.4.5 DISPLAY_ON
      6. 6.4.6 PARKING
      7. 6.4.7 SHUTDOWN
    5. 6.5 Register Maps
      1. 6.5.1 System Status Registers
      2. 6.5.2 ADC Control
      3. 6.5.3 General Fault Status
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 HUD
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Application Design Considerations
          1. 7.2.1.2.1 Photodiode Considerations
          2. 7.2.1.2.2 LED Current Measurement
          3. 7.2.1.2.3 Setting the Current Limit
          4. 7.2.1.2.4 Input Voltage Variation Impact
          5. 7.2.1.2.5 Discontinuous Mode Photo Feedback Considerations
          6. 7.2.1.2.6 Transimpedance Amplifiers (TIAs, Usage, Offset, Dark Current, Ranges, RGB Trim)
      2. 7.2.2 Headlight
        1. 7.2.2.1 Design Requirements
  9. 8 Power Supply Recommendations
    1. 8.1 TPS99000-Q1 Power Supply Architecture
    2. 8.2 TPS99000-Q1 Power Outputs
    3. 8.3 Power Supply Architecture
  10. 9 Layout
    1. 9.1 Layout Guidelines
      1. 9.1.1 Power/High Current Signals
      2. 9.1.2 Sensitive Analog Signals
      3. 9.1.3 High-Speed Digital Signals
      4. 9.1.4 High Power Current Loops
      5. 9.1.5 Kelvin Sensing Connections
      6. 9.1.6 Ground Separation
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

6.3.1.4 Discontinuous Mode Operation

Discontinuous mode is used to achieve lower dimming levels. It replaces the constant block of light during a bit slice with a series of light pulses of controlled amplitude, as illustrated in Figure 6-15. The number of pulses is controlled by the DLPC23x-Q1 software.

TPS99000-Q1 Comparison of Continuous and Discontinuous Operation at Equivalent BrightnessFigure 6-15 Comparison of Continuous and Discontinuous Operation at Equivalent Brightness

Figure 6-15 is an example diagram showing the Discontinuous Mode signals generating eight pulses that are equivalent in brightness.

In discontinuous mode, the controller produces discrete pulses of light with fixed off times between pulses. The amount of light that these pulses produce can be precisely controlled to reach low dimming levels. Two control loops are used to create uniform light pulses:

  • Peak current limit loop to create a desired current level in the inductor before it flows through the LED.
  • Photo feedback loop to terminate each pulse when the desired light pulse level is achieved.
The initial inductor current and peak light threshold are independently adjustable for each color. See Figure 6-16 and Figure 6-17.

TPS99000-Q1 Discontinuous Operation DLPC23x-Q1 to TPS99000-Q1 SignalsFigure 6-16 Discontinuous Operation DLPC23x-Q1 to TPS99000-Q1 Signals
TPS99000-Q1 Discontinuous Mode Operation Inductor Current/LED VoltageFigure 6-17 Discontinuous Mode Operation Inductor Current/LED Voltage

Discontinuous mode consists of a series of triangular pulses of light. The DLPC23x-Q1 is in charge of requesting and counting the total number of pulses. A bit slice begins with the low resistance shunt enable (S_EN1) on, and with an RGB color selected. Then DLPC23x-Q1 asserts D_EN. This causes the TPS99000-Q1 to turn on the LED current drive (DRV_EN) and the system charges the inductor into the low resistance shunt until the peak current limit (as programmed with ILIM DAC) is reached. Then after a programmable amount of time the DLPC23x-Q1 drives S_EN low, forcing inductor current to flow through the selected LED.

The TPS99000-Q1 detects the falling edge of S_EN from the DLPC23x-Q1 and issues an on/off/on toggle of the DRV_EN signal. This allows current to flow through the inductor and increases the voltage at the LED anode. When the LED forward voltage is achieved, it begins to emit light. Once the photo feedback loop (TIA, photo feedback comparator, photo feedback DAC) senses the desired light threshold has been crossed, the S_EN1 signal is re-asserted high, and the light pulse is terminated.

The COMPOUT signal going low indicates to the DLPC23x-Q1 that the pulse has been completed. The DLPC23x-Q1 immediately sets S_EN output high (which sets TPS99000-Q1 output S_EN1 high), then waits for a programmable length of time. After that period of time, the DLPC23x-Q1 will decide either to drive D_EN low and wait for the next bit slice or issue a request for a new pulse by placing the S_EN output low. When S_EN output is placed low, the TPS99000-Q1 places S_EN1 low (forcing current through LED) and toggles DRV_EN to request a new peak limit current pulse cycle. This process repeats until the correct number of pulses for the given bit slice have been completed.

In very low brightness operation, the TPS99000-Q1 SYNC (LM3409 COFF) timer is disabled. As a result, DRV_EN is only toggled at the beginning of each light pulse. This synchronizes the inductor and LED current. This synchronization keeps LED pulse heights very consistent from one video frame to the next, preventing flicker.