POWER AND LINEAR IC SOLUTIONS

Power LED Driver Delivers Constant Brightness

Infineon's TLE 4309 G is designed to drive LEDs with a constant current, creating constant brightness and colour and extending LED lifetimes.

The TLE 4309 G provides designers with a constant current source capable of driving LEDs with currents of up to 500mA. The current is adjusted via an external resistor, while LED brightness and colour are easily regulated by modulating the duty cycle of a PWM (Pulse Width Modulation) signal applied to the chip's PWM input pin. A low drop voltage ensures full LED brightness, even at low battery voltages.

The IC provides a superior solution to driving high power LEDs compared to a traditional resistor-based approach in which current can continue to rise as supply voltage increases. Inbuilt functionality includes protection against overload, short circuit and reverse polarity conditions. Further protection is supplied in the form of a chip monitoring circuit. This circuit protects both the IC and the LED by shutting down when an overtemperature condition occurs.

In addition to regulating LED brightness, the PWM input pin can also be used as a sleep and enable input. PWM = Low sets the TLE 4309 G into sleep mode resulting in a very low current consumption of under 1µA (typical). Due to the high impedance of the PWM input, the pin can also be used as an enable input.


Infineon TLE 4309 G Block Diagram

Supplied in a P-TO263-7 power package, the TLE 4309 G is capable of withstanding harsh application environments and has an operating temperature range of -40°C to +125°C.

Features

• Adjustable constant current: up to 500mA
• Pulse Width Modulation input for brightness control
• 1μA current consumption in sleep mode
• Fully suitable for use in automotive and industry applications
• Overtemperature protection
• Reverse polarity proof
• Input voltage range up to 24V
• Short circuit protection to GND and VCC
• Low drop voltage: Full brightness at low battery voltage
• Temperature range: -40°C to +125°C
• Power package P-TO263-7

Applications

• Traffic lights
• Street marker lights
• Displays
• General lighting
• LED signage

For further information, including the TLE4309 G Product Brief, please click here