A Compact DC–DC Converter Using Low-Temperature Poly-Si Oxide Thin-Film Transistors

A compact DC-DC converter has been designed based on low-temperature poly-Si oxide (LTPO) thin film transistors (TFTs). It consists of 6 TFTs, 4 amorphous InGaZnO (a-IGZO) TFTs and 2 low-temperature poly-Si (LTPS) TFTs, along with 4 pumping capacitors (CPUMP) of 5pF. Two clock signals have been used with a switching frequency (fSW) of 500kHz for the LTPO DC-DC converter. The measured output voltage (VOUT) of 14.5V and output power (POUT) of
$790~\mu \text{W}$
are achieved for 3V input voltage (VIN measured by an oscilloscope with 12pF load capacitance. It shows a maximum power efficiency of 83.3% at the load current of
$90~\mu \text{A}$
. The LTPO DC-DC converter using small CPUMP performs well with reduced area of 0.45mm2.