The DLPC23xS-Q1 is a controller for the DMD and the timing of the RGB LEDs in the HUD. It requests the proper timing and amplitude from the LEDs to achieve the requested color and brightness from the HUD across the entire operating range. It synchronizes the DMD with these LEDs to display full-color video content sent by the host.

The DLPC23xS-Q1 receives command and input video data from a host processor in the vehicle. Read and write (R/W) commands can be sent using either the I²C bus or SPI bus. The bus that is not being used for R/W commands can be used as a read-only bus for diagnostic purposes. Input video can be sent over an OpenLDI bus or a parallel 24-bit bus. The SPI flash memory provides the embedded software for the DLPC23xS-Q1’s embedded processor, color calibration data, and default settings. The TPS99000S-Q1 provides diagnostic and monitoring information to the DLPC23xS-Q1 using an SPI bus and several other control signals such as PARKZ, INTZ, and RESETZ to manage power-up and power-down sequencing. The DLPC23xS-Q1 interfaces to a TMP411 through I²C for temperature information.

The outputs of the DLPC23xS-Q1 are LED drive information to the TPS99000S-Q1, control signals to the DMD, and monitoring and diagnostics information to the host processor. Based on a host requested brightness and the operating temperature, the DLPC23xS-Q1 determines the proper timing and amplitudes for the LEDs. It passes this information to the TPS99000S-Q1 using an SPI bus and several additional control signals such as D_EN, S_EN, and SEQ_STRT. It controls the DMD mirrors by sending data over a SubLVDS bus. It can alert the host about any critical errors using a HOST_IRQ signal.

The TPS99000S-Q1 is a highly-integrated mixed-signal IC that controls DMD power, the analog response of the LEDs, and provides monitoring and diagnostics information for the HUD system. The power sequencing and monitoring blocks of the TPS99000S-Q1 properly power up the DMD, provide accurate DMD voltage rails, as well as monitor the system’s power rails during operation. The integration of these functions into one IC significantly reduces design time and complexity. The highly accurate photodiode (PD) measurement system and the dimming controller block precisely control the LED response. This enables a DLP technology HUD to achieve a very high dimming range (> 5000:1) with accurate brightness and color across the temperature range of the system. Finally, the TPS99000S-Q1 has several general-purpose ADCs that developers can use for system-level monitoring, such as over-brightness detection.

The TPS99000S-Q1 receives inputs from the DLPC23xS-Q1, power rail voltages for monitoring, a photodiode that is used to measure LED response, the host processor, and potentially several other ADC ports. The DLPC23xS-Q1 sends commands to the TPS99000S-Q1 over an SPI port and several other control signals. The TPS99000S-Q1 includes watchdogs to monitor the DLPC23xS-Q1 and verify it is operating as expected. The power rails are monitored by the TPS99000S-Q1 to detect power failures or glitches and request a proper power down of the DMD in case of an error. The photodiode’s current is measured and amplified using a transimpedance amplifier (TIA) within the TPS99000S-Q1. The host processor can read diagnostics information from the TPS99000S-Q1 using a dedicated SPI bus, adding an independent monitoring path from the host processor. Additionally the host can request the system to be turned on or off using a PROJ_ON signal. The TPS99000S-Q1 has several general-purpose ADCs that can be used to implement other system features such as over-brightness and over-temperature detection.

The outputs of the TPS99000S-Q1 are LED drive signals, diagnostic information, and error alerts to the DLPC23xS-Q1. The TPS99000S-Q1 has signals connected to the LM3409 buck controller for high power LEDs and to discrete hardware that control the LEDs. The TPS99000S-Q1 can output diagnostic information to the host and the DLPC23xS-Q1 over two SPI buses. It also has signals such as RESETZ, PARKZ, and INTZ that can be used to trigger power down or reset sequences.

The DMD is a micro-electro-mechanical system (MEMS) device that receives electrical signals as an input (video data) and produces a mechanical output (mirror position). The electrical interface to the DMD is a SubLVDS interface driven with the DLPC23xS-Q1. The mechanical output is the state of more than 1.3 million mirrors in the DMD array that can be tilted ±12°. In a projection system, the mirrors are used as pixels to display an image.