Overview
The LP8864S-Q1 is an automotive high-efficiency LED driver designed by Texas Instruments. This device is specifically tailored for automotive display LED backlight applications, including infotainment systems, clusters, and heads-up displays (HUD). It features a boost controller and four high-precision current sinks, enabling phase shifting based on the number of channels in use. The LED brightness can be controlled globally through either the I²C interface or PWM input. The device is AEC-Q100 qualified, ensuring reliability and performance across a wide temperature range of -40°C to +125°C.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Voltage on VSENSE_N, SD, UVLO | -0.3 | - | VSENSE_P + 0.3 | V |
| IQ Shutdown mode current, VDD pin | 1 | 5 | - | µA |
| IQ Active mode current, VDD pin (FSW = 303 kHz, PWM = H, BOOST-FET IPD25N06S4L-30, Charge Pump Disabled) | 15 | 65 | - | mA |
| IQ Active mode current, VDD pin (FSW = 2200 kHz, PWM = H, BOOST-FET IPD25N06S4L-30, Charge Pump Enabled) | 65 | 104 | - | mA |
| VCPUMP Voltage accuracy (VDD = 3.0 to 3.6V; ILOAD = 1 to 50mA) | 4.8 | 5 | 5.2 | V |
| VCPUMP UVLO threshold (VCPUMP falling edge) | 3.95 | 4.2 | 4.4 | V |
| VDD UVLO threshold (VDD falling) | 2.68 | 2.8 | 2.92 | V |
| TSD Thermal shutdown threshold (Temperature rising) | 150 | 165 | 180 | °C |
| Maximum output current per LED driver | - | - | 150 | mA |
| Switching frequency of the boost regulator | 100 kHz | - | 2.2 MHz | - |
Key Features
- AEC-Q100 qualified for automotive applications with a temperature range of -40°C to +125°C.
- Four high-precision current sinks with automatic phase shifting based on the number of channels in use.
- Global LED brightness control via I²C interface or PWM input.
- Adaptive output voltage control to minimize power consumption.
- Wide-range adjustable frequency to avoid disturbance in the AM radio band.
- Hybrid PWM dimming and analog current dimming to reduce EMI, extend LED lifetime, and increase optical efficiency.
- Support for up to 150mA per output, with the ability to tie outputs together for higher current LEDs.
- Configurable LED PWM frequency and LED string current through external resistors.
- Automatic selection of phase shift mode based on the number of connected LED strings.
- Fault detection features including open-string, shorted LED, LED short-to-ground, and overcurrent/overvoltage protection.
- Thermal shutdown and device undervoltage protection.
- Control of a power-line FET to reduce battery leakage and provide isolation and protection in fault events.
Applications
- Automotive infotainment systems.
- Automotive clusters and instrument panels.
- Heads-up displays (HUD).
- Other automotive display LED backlight applications.
Q & A
- What is the temperature range for the LP8864S-Q1?
The LP8864S-Q1 operates within a temperature range of -40°C to +125°C.
- How is the LED brightness controlled in the LP8864S-Q1?
The LED brightness can be controlled globally through either the I²C interface or PWM input.
- What is the maximum output current per LED driver in the LP8864S-Q1?
The maximum output current per LED driver is up to 150mA.
- How does the LP8864S-Q1 adjust its boost voltage?
The device adjusts its boost voltage automatically to the minimum necessary level needed to drive the LED strings by continuously monitoring all the LED output voltages.
- What types of fault detection does the LP8864S-Q1 support?
The LP8864S-Q1 supports fault detection for open-string, shorted LED, LED short-to-ground, overcurrent, overvoltage, and thermal shutdown.
- How is the switching frequency of the boost regulator configured?
The switching frequency of the boost regulator can be set between 100kHz and 2.2MHz using the BST_FSET resistor.
- What is the purpose of the INT pin in the LP8864S-Q1?
The INT pin is used to report faults to the system and can be cleared with the I²C interface or on the falling edge of the EN pin.
- Can the LP8864S-Q1 control a power-line FET?
Yes, the LP8864S-Q1 can control a power-line FET to reduce battery leakage and provide isolation and protection in fault events.
- What is the significance of AEC-Q100 qualification for the LP8864S-Q1?
AEC-Q100 qualification ensures that the device meets stringent automotive standards for reliability and performance.
- How does the LP8864S-Q1 reduce EMI and extend LED lifetime?
The device uses hybrid PWM dimming and analog current dimming to reduce EMI, extend LED lifetime, and increase optical efficiency.
