To configure the lpGBT chips that will be used on the peripheral electronics boards of the ATLAS-HGTD upgrade for the HL-LHC, a miniature and isolated USB programmer board for lpGBT (UPL) was developed based on an USB-protocol converter. Compared with the currently-used lpGBT programmer piGBT, the UPL has the advantages of compact profile, electrical isolation and cross-platform compatibility. In addition, it has a 14-pin header connector with one I2C port and six GPIOs available, and a dedicated GUI for lpGBT configuration. In particular, its isolation performance is completely determined by its I2C isolator and power isolator, both of which have the high isolation voltages of more than 1000 V AC RMS and 2000 V DC. The UPL was extensively tested by configuring a lpGBT-based board, and the lpGBT can always be successfully configured, and the bit error rate of the data transmission is always less than 1 × 10−13.