US 12,073,804 B2
Signal level shift conversion circuit for display driver and display device converting input voltage signal at synchronized timing
Hiroshi Tsuchi, Yokohama (JP); and Hayato Koizumi, Yokohama (JP)
Assigned to LAPIS Technology Co., Ltd., Yokohama (JP)
Filed by LAPIS Technology Co., Ltd., Yokohama (JP)
Filed on Dec. 19, 2021, as Appl. No. 17/555,485.
Claims priority of application No. 2020-216101 (JP), filed on Dec. 25, 2020.
Prior Publication US 2022/0208136 A1, Jun. 30, 2022
Int. Cl. G09G 3/36 (2006.01)
CPC G09G 3/3614 (2013.01) [G09G 3/3696 (2013.01); G09G 2310/0289 (2013.01); G09G 2310/08 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A signal level conversion circuit that level-shifts an amplitude of an input voltage signal, comprising:
a first level shift circuit that generates a voltage signal obtained by converting the amplitude of the input voltage signal into an amplitude between a first power supply voltage having a first polarity with respect to a predetermined reference power supply voltage and a second power supply voltage of a second polarity having a polarity opposite to the first polarity with respect to the reference power supply voltage;
a second level shift circuit that generates a voltage signal obtained by converting the amplitude of the voltage signal into an amplitude between the reference power supply voltage and the first power supply voltage as a first polarity voltage signal;
a third level shift circuit that outputs a voltage signal obtained by converting the amplitude of the first polarity voltage signal into an amplitude between a third power supply voltage of the first polarity of which a voltage difference from the reference power supply voltage is larger than that of the first power supply voltage and the reference power supply voltage as a high voltage signal of the first polarity;
a fourth level shift circuit that generates a voltage signal obtained by converting the amplitude of the voltage signal generated by the first level shift circuit into an amplitude between the reference power supply voltage and the second power supply voltage as a second polarity voltage signal; and
a fifth level shift circuit that outputs a voltage signal obtained by converting the amplitude of the second polarity voltage signal into an amplitude between a fourth power supply voltage of the second polarity of which a voltage difference from the reference power supply voltage is larger than that of the second power supply voltage and the reference power supply voltage as a high voltage signal of the second polarity,
wherein the signal level conversion circuit is constituted by transistors each having a withstand voltage lower than a voltage difference between the third power supply voltage of the first polarity and the fourth power supply voltage of the second polarity,
wherein the third power supply voltage is greater than the first power supply voltage, the first power supply voltage is greater than the reference power supply voltage, the reference power supply voltage is greater than the second power supply voltage, and the second power supply voltage is greater than the fourth power supply voltage.