BCR503E6327: A Comprehensive Technical Overview and Application Note
The BCR503E6327 from Infineon Technologies represents a state-of-the-art, three-terminal constant current regulator designed for robust and efficient LED driving applications. This device simplifies circuit design by integrating a high-performance regulator with a power MOSFET on a single silicon chip, offering a compact and highly reliable solution for maintaining constant current over a wide voltage range.
Technical Overview
At its core, the BCR503E6327 is engineered to provide a fixed output current of 50 mA, which is precisely set by an internal resistor. This eliminates the need for external current-setting components, thereby reducing the bill of materials (BOM), PCB footprint, and overall system cost. The device operates within an input voltage range from 8 V to 40 V, making it exceptionally versatile for a broad spectrum of low-power lighting applications.
A key feature of this IC is its low dropout voltage, which ensures high efficiency even as the input voltage approaches the output level. The integrated MOSFET is optimized for low saturation, further enhancing thermal performance and energy efficiency. The device is housed in a SOT-143R small surface-mount package, which is ideal for space-constrained designs. Furthermore, it boasts excellent temperature stability, ensuring consistent current regulation and LED brightness across a wide operating temperature range from -40 °C to +150 °C. Built-in protection features, including over-temperature shutdown, safeguard the device and the connected LEDs under fault conditions.
Application Note
The primary application for the BCR503E6327 is as a simple and effective linear constant current source for driving single or multiple series-connected LEDs. Its design is particularly advantageous in scenarios requiring stable illumination without the complexity of a switching regulator.
A typical application circuit is remarkably straightforward. The input voltage (VIN) is connected to the Source terminal (S), the Cathode of the LED string is connected to the Drain terminal (D), and the Gate terminal (G) is typically left open. The internal circuitry automatically regulates the current flowing from S to D to a constant 50 mA. For example, to drive a string of three white LEDs (each with a typical forward voltage of 3.2V), a minimum input voltage of just over 9.6V plus the dropout voltage is required. The device will then maintain the current at 50 mA even if the input voltage fluctuates within its specified range.
This makes the BCR503E6327 an ideal choice for:
Automotive Interior Lighting: For dashboard backlighting, ambient lighting, and switch illumination due to its wide operating voltage range and robustness.
Consumer Appliances: For status indicators and decorative lighting.
24V Industrial Lighting Systems: Providing a simple, reliable driver for indicator lights and small light strips.
Battery-Powered Devices: Where stable light output is required as the battery voltage declines.
ICGOODFIND: The BCR503E6327 stands out as an exceptionally simple and cost-optimized solution for low-power, linear LED driving. Its integrated design, requiring no external components, offers designers a path to minimize board space and simplify assembly. While its linear operation makes it best suited for applications where power dissipation is manageable, its robustness, wide voltage range, and built-in protections make it a superior choice for automotive and industrial environments where reliability is paramount.
Keywords: Constant Current Regulator, LED Driver, Automotive Lighting, SOT-143R, Low Dropout Voltage.
