TI LED171596A 96個LED陣列驅(qū)動解決方案

TI公司的LED171596A是用于RGB和白光LED的96個（24x4） LED陣列驅(qū)動器，具有單獨的通路控制，支持4個低電阻高邊開關(guān)和24個低邊電流沉，每路可提供多達15mA的連續(xù)電流，電流匹配度±5%，I2C，SPI和PWM亮度控制模式，具有擴展的保護功能如開路和短路LED故障檢測和熱關(guān)斷保護。主要用在控制面板照明和局部地區(qū)調(diào)光LED背景光驅(qū)動器。本文介紹了LED171596A主要特性，功能框圖和應(yīng)用電路，亮度通路圖以及評估板LED171596A EVM特性，電路圖，材料清單和PCB設(shè)計圖。

LED171596A 96-LED Matrix Driver for RGB and White LEDs.The LED171596A is a 96 channel matrix LED driverwith independent channel control， designed fordriving locally dimmed displays. The device sports 4low-resistance high side switches and 24 low side current sinks that can deliver up to 15 mA ofcontinuous current per channel. The driver has 9-bitduty cycle and 8-bit current control of each low-sideLED current sink.

Each current sink can be individually controlledthrough the I2C-compatible or SPI interface， but alsohas the capability to be controlled with a single valuethrough the global brightness control register. Thisglobal brightness control also passes through abrightness sloper function to create optically smoothbrightness transitions without the need for multipleregister writes.

The LED171596A is a LED driver that can individually control up to 96 LEDs. To control the 96 LEDs in a 4 × 24matrix the device uses four high-side PMOS switches and 24 low-side programmable current sinks. Each of thelow-side current sinks has independent 9-bit duty cycle and 8-bit current control. The individually duty and currentvalues can be controlled through the SPI or I2C-compatible interfaces.

The four high-side switches allow the LED171596A to time multiplex four groups of 24 LEDs. Maximum peakcurrent is set with ISET （with 60 mA maximum）， but the maximum average current delivered to each LED is 15mA （ILED_MAX /4）。

The individual LED brightness is internally multiplied with a global brightness register value. This allows thecontrol of all the LEDs at once with a single master brightness register or PWM input signal. This masterbrightness also passes through a brightness sloper function to create optically smooth brightness transitionswithout the need for multiple register writes.

Device control interface features：

? EN is an enable input for LED171596A

? INT is an open-drain interrupt output （indicating fault condition detection or sloper completion， for example）

? IFSEL_LATCH is a dual function pin which is used for selecting between I2C-compatible and SPI after risingedge of EN pin then can be used to latch register changes.

– For interface selection the IFSEL pin status is checked after rising edge of EN pin. Note： IFSEL must bestatic for tIFSEL_HOLD max time following EN rising edge.

– If IFSEL is pulled low （0） the 4-wire SPI interface is selected （SCLK， MISO， MOSI， and SS）。

– If IFSEL is pulled high （1） the 2-wire I2C-compatible interface is selected.

– An optional PWM input is available at SS/PWM when I2C is selected.

– When I2C is selected， the ADDR pin is used to select between three alternate I2C slave addresses.

– In normal mode the pin functions as a LATCH signal to trigger updates of SRAM buffers.

– LATCH occurs on the rising edge. Minimum latch pulse length is tLATCH ns.

– Alternatively a LATCH register bit can be used instead of pin control. Wait for latch_busy to be clearedin STATUS register before writing to SRAM when using LATCH register bit.

? ISET pin to set master LED current level for all LEDs.

Protection features of the LED171596A device include：

? Open-LED and shorted-LED detections

– When detected （unless masked）， the INT pin goes low， and status registers show that LEDs are OPEN orSHORT. Faulty LEDs can then be disabled via register bits， and fault status can be cleared.

? Thermal shutdown in case of die overtemperature.

LED171596A主要特性：

1? 24 High-Precision Current Sinks

– 60-mA Peak Current per Channel

– Current Matching ±5%

– Independent 9-Bit Duty Cycle PWM and 8-BitLED Current Control

– 7-V Tolerant

– ISET Resistor to Set Global Current

– Ghosting Cancellation

? Four Low Resistance High Side Series Switches

– 1.5-A Current-Rated PMOS

? I2C， SPI， and PWM Brightness Control Modes

? Extensive Protection Features

– Open and Shorted LED Fault Detection

– Thermal Shutdown Protection

LED171596A應(yīng)用：

? Control Panel Illumination

? Local Dimming LED Backlight Drivers

圖1.LED171596A功能框圖

圖2.LED171596A簡化電路圖

圖3.LED171596A典型應(yīng)用電路圖

圖4.LED171596A亮度通路圖

評估板LED171596A EVM

The Texas Instruments LED171596A evaluation module （EVM） helps designers evaluate the operationand performance of the LED171596A 96-LED driver. The LED171596A is an LED matrix driver that canindividually control up to 96 LEDs. To control the 96 LEDs it uses four high-side PMOS switches and 24low-side programmable current sinks. The driver has 9-bit duty cycle and 8-bit current control of each lowside LED current sink. They can be individually controlled through the I2C-compatible or SPI interface.The EVM contains one LED171596A and one LEDARRAYEVM with 96 white LEDs.

圖5.評估板LED171596A EVM外形圖

圖6.評估板LED171596A EVM電路圖（1）

圖7.評估板LED171596A EVM電路圖（2）

評估板LED171596A EVM材料清單：

圖8.評估板LED171596A EVM PCB設(shè)計圖（1）

圖9.評估板LED171596A EVM PCB設(shè)計圖（2）

圖10.評估板LED171596A EVM PCB設(shè)計圖（3）

圖11.評估板LED171596A EVM PCB設(shè)計圖（4）

圖12.評估板LED171596A EVM PCB設(shè)計圖（5）