US 12,334,928 B2
Level shifter
Chien-Hui Tsai, Hsinchu (TW); Hung-Chen Chu, Hsinchu (TW); and Yung-Tai Chen, Hsinchu (TW)
Assigned to REALTEK SEMICONDUCTOR CORPORATION, Hsinchu (TW)
Filed by REALTEK SEMICONDUCTOR CORPORATION, Hsinchu (TW)
Filed on Feb. 2, 2024, as Appl. No. 18/430,700.
Application 18/430,700 is a division of application No. 17/727,909, filed on Apr. 25, 2022, granted, now 11,929,747.
Claims priority of application No. 110124347 (TW), filed on Jul. 2, 2021.
Prior Publication US 2024/0171159 A1, May 23, 2024
Int. Cl. H03K 3/037 (2006.01); H03K 19/0185 (2006.01)
CPC H03K 3/0375 (2013.01) [H03K 19/018528 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A level shifter comprising a latch circuit, a protection circuit, and an input circuit, wherein:
the latch circuit is coupled between a high-voltage terminal and the protection circuit, wherein a voltage at the high-voltage terminal is a high voltage in an operating mode;
the protection circuit includes a first protection transistor pair and a second protection transistor pair and configured to operate according to a voltage at a medium-voltage terminal, wherein the first protection transistor pair is set between the latch circuit and a pair of signal output terminals, the second protection transistor pair is set between the pair of signal output terminals and the input circuit, and the pair of signal output terminals includes a first output terminal and a second output terminal;
in the operating mode, the voltage at the medium-voltage terminal is a medium voltage, the first output terminal and the second output terminal are used for outputting a first output signal and a second output signal respectively, a voltage of each of the first output signal and the second output signal falls within an output voltage range, the output voltage range is between the high voltage and a predetermined voltage;
the input circuit includes an input transistor pair coupled between the second protection transistor pair and a low-voltage terminal and configured to operate according to a pair of input signals;
in the operating mode, a voltage at the low-voltage terminal is the predetermined voltage, the pair of input signals includes a first input signal and a second input signal, a voltage of each of the first input signal and the second input signal falls within an input voltage range, and the input voltage range is between the medium voltage and the predetermined voltage;
the predetermined voltage is a low voltage higher than a ground voltage; and
in a power down mode, the voltage at the high-voltage terminal is pulled to the medium voltage, the voltage at the medium-voltage terminal is pulled to the ground voltage, and the voltage at the low-voltage terminal is pulled to the medium voltage.