High-Brightness LED Matrix Manager for Automotive Headlight Systems
1 Features
- 12 Series LED Bypass Switches
- Multi-Drop UART Communication Interface
- Programmable 10-bit PWM Dimming
- Individual Turn-on and Turn-off Times
- Inherent Phase Shift Capability
- Device-to-Device Synchronization
- LED Open/Short Detection and Protection
- Fault Reporting
- AEC-Q100 Grade 1
- Thermally Enhanced Package
- 48-pin, TQFP, Exposed Pad Package
2 Applications
- Automotive headlight systems
- High-Brightness LED Matrix Systems
3 Description
The TPS92661 device is a compact, highly-integrated solution for shunt FET dimming for large arrays of high-brightness LEDs in applications such as automotive headlights.
The TPS92661 device includes a 12-switch series array for bypassing individual LEDs in the string and a serial communication interface for control and management by a master microcontroller.
An on-board charge pump rail that can float up to 67 V above GND provides the LED bypass switch gate drive.The low on-resistance (RDS(on)) of the bypass switch minimizes conduction loss and power dissipation.
The TPS92661 device contains a multi-drop universal asynchronous receiver transmitter (UART) for serial communication. The turn-on and turn-off times are programmable for each individual LED in the string. The PWM frequency is adjustable via an internal register and multiple devices can be synchronized to the same frequency and phase.
The TPS92661 device features open LED protection as well as open and short LED fault reporting via the serial interface.
The TQFP package features a feed-through topology to enable easy routing of signals on single-layer metal core LED load boards.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| TPS92661-Q1 | PHP (48) | 7.00 mm × 7.00 mm |
- For all available packages, see the orderable addendum at the end of the data sheet.
Simplified System Schematic
4 Revision History
Changes from * Revision (September 2014) to A Revision
- Added output current range specifications in Recommended Operating Conditions tableGo
- Added updated text to the section UART Communications Reset to indicate that a communications reset should only be sent when the device is not transmitting dataGo
5 Pin Configuration and Functions
Pin Functions
| PIN | I/O | DESCRIPTION | |
|---|---|---|---|
| NAME | NO. | ||
| ADR0 | 22 | I | Least significant bit (LSB) of device address. Connect to VIN or GND. |
| ADR1 | 15 | I | Second bit of device address. Connect to VIN or GND. |
| ADR2 | 16 | I | Most significant bit (MSB) of device address. Connect to VIN or GND. |
| CLK | 8 | I | System clock. This clock is provided externally (by the microcontroller unit or an external oscillator) and is the primary clock for the device. |
| 29 | |||
| CPP | 1 | I | Charge pump output. Bypass with a ceramic capacitor with a minimum value of 0.1 µF to LED12. |
| EN | 4 | I | Enable pins. The device is active when EN is high or in reset when EN is low. Connect to microcontroller unit output or tie to VCC or VIN for enable at power-up. |
| 33 | |||
| GND | 3, 5, 7, 9, 11, 24, 26, 28, 30, 32, 34 | — | Device system ground. All pins MUST be connected for proper operation. |
| LED0 | 36 | O | Connect to cathode of LED1. |
| LED1 | 37 | O | Connect to anode of LED1 and cathode of LED2. |
| LED2 | 38 | O | Connect to anode of LED2 and cathode of LED3. |
| LED3 | 39 | O | Connect to anode of LED3 and cathode of LED4. |
| LED4 | 40 | O | Connect to anode of LED4 and cathode of LED5. |
| LED5 | 41 | O | Connect to anode of LED5 and cathode of LED6. |
| LED6 | 42 | O | Connect to anode of LED6 and cathode of LED7. |
| LED7 | 43 | O | Connect to anode of LED7 and cathode of LED8. |
| LED8 | 44 | O | Connect to anode of LED8 and cathode of LED9. |
| LED9 | 45 | O | Connect to anode of LED9 and cathode of LED10. |
| LED10 | 46 | O | Connect to anode of LED10 and cathode of LED11. |
| LED11 | 47 | O | Connect to anode of LED11 and cathode of LED12. |
| LED12 | 48 | O | Connect to anode of LED12. |
| NC | 2, 17, 18, 19, 20, 21, 35 | — | No connection. |
| RX | 12 | I/O | Received data pins. Connect one RX pin of first device to microcontroller unit TX output and use second pin to connect to a RX pin of the second device. All other devices use both pins to route the RX line through each device. |
| 25 | |||
| SYNC | 6 | I/O | Synchronization pins. Allows synchronization of multiple TPS92661 devices on the same network. May be driven by the microcontroller unit, or one TPS92661 device may be programmed via the serial interface to provide this pulse. Only one device should drive this signal. May be left unconnected if not used. |
| 31 | |||
| TX | 10 | I/O | Transmitted data pins. Connect one TX pin of first device to microcontroller unit RX input and use second pin to connect to a TX pin of the second device. All other devices use both pins to route the TX line through each device. This pin requires a 100kΩ pull-up resistor. |
| 27 | |||
| VCC | 13 | O | Output of the on-board 3.3-V LDO. This pin requires a ceramic output capacitor with a value of 0.1 µF or greater. Tie to the VIN pin for 5-V microcontroller unit systems. |
| VIN | 14 | I | 5-V power supply input for device. Bypass with a ceramic capacitor with a minimum value of 0.1 µF. |
| 23 | |||
| Thermal Pad | - | Connect to system GND. | |