Mikroe Boost 3 Click has a boost converter with an integrated current mirror function. The board features the Texas Instruments TPS61391 700kHz pulse-width modulating (PWM) Step-Up converter with a 70V switch FET with an input voltage up to 5.5V. The TPS61391 includes an accurate current mirror, with two selectable gain options (1:5 or 4:5). It provides high optical-power protection with an additional FET in series with the APD power path, with the typical response time of 0.5µs.