A Negative Low-Voltage Power Supply Integrated With High-Voltage Devices

A negative low-voltage power supply with the highest positive potential as reference is proposed in this paper. The proposed power supply is integrated with high-voltage devices. When the high-voltage devices are applied as a switch, negative low-voltage pulses are first produced from the positive high voltage applied on devices by using the designed junction termination of the devices. Then, a stable negative power voltage is finally produced from the negative low-voltage pulses by using a designed low-voltage circuit (LVC) that consists of pMOS and capacitors. The mechanism of the proposed power supply is verified using an insulated-gate bipolar transistor (IGBT) device, whose junction termination is realized by the optimum variation lateral doping technique [breakdown voltage (BV) = 2100 V]. The simulation results show that the power supply can achieve a stable value of -6.2 V whenever the IGBT is operated at 500 or 1500 V. Moreover, an experimental sample of LVC is fabricated using a 0.5-mu m BiCMOS process. The transient experiments confirm that LVC can convert negative voltage pulses with different periods and amplitudes to a stable negative low voltage. The steady-state experiments show that the input BV of LVC is 57 V and its output voltages can be adjusted from -2 to -14.5 V.