ADM00435 - 

The MCP1643 Synchronous Boost LED Constant Current Regulator Evaluation Board is used to evaluate and demonstrate Microchip Technology’s MCP1643 device. This board demonstrates the MCP1643 in a boost converter application supplied by one AA battery, or from an external voltage source, which drives an LED with three selectable currents. This evaluation board was developed to help engineers reduce the product design cycle time.
Four output currents can be selected: 25, 50, 75 and 100 mA. The output current can be changed with a dual switch that changes the external LED current sense equivalent resistance. An enable switch is used to enable and disable the converter. When enabled, the MCP1643 will regulate the output current; when disabled, the MCP1643 disconnects the path from input to output for “true-disconnect”. In this state, the current consumed from the battery is 1 μA, typically.

Devices Supported: MCP1643

Features:

It can be powered by one-cell Alkaline, NiCd, or NiMH batteries, or by external power supply

Input voltage range, VIN: 0.35 V to 2.5 V, with VIN < VOUT

Start-up voltage: 0.65 V

Fixed output current: 25 mA 50 mA, 75 mA or 100 mA, selected using a mini-dip switch on board

PWM Switching Frequency: 1 MHz

Enable state selectable using mini-dip switch on board

1.6 A Peak Input Current Limit

Over-temperature Protection (if the die temperature exceeds 150°C, 25°C hysteresis)

Mechanical battery reverse polarity protection