US 12,381,559 B2
Input/output circuit
Pei-Shin Chiu, Hsinchu (TW); Te-Chang Wu, Hsinchu County (TW); Chih-Yuan Chung, Hsinchu (TW); and Wen-Ching Huang, Hsinchu County (TW)
Assigned to UNITED MICROELECTRONICS CORP., Hsinchu (TW)
Filed by UNITED MICROELECTRONICS CORP., Hsinchu (TW)
Filed on Mar. 28, 2023, as Appl. No. 18/127,275.
Claims priority of application No. 112107306 (TW), filed on Mar. 1, 2023.
Prior Publication US 2024/0297650 A1, Sep. 5, 2024
Int. Cl. H03K 19/0185 (2006.01); H03K 19/003 (2006.01)
CPC H03K 19/018521 (2013.01) [H03K 19/00315 (2013.01); H03K 19/018585 (2013.01)] 13 Claims
OG exemplary drawing
 
1. An input/output circuit (I/O circuit), comprising:
an input/output pad (I/O) pad), having a pad voltage, and having a plurality of operating modes, the operating modes comprise an input mode and an output mode, and the input mode comprises a normal input mode and a tolerance mode;
a first control circuit, for providing a first control signal in response to the pad voltage and a supply voltage;
a first P-type transistor, having a first source, a first drain, a first gate and a first body region, the first source receives the supply voltage, and the first body region receives the first control signal; and
a second P-type transistor, having a second source, a second drain, a second gate and a second body region, the second source is connected to the first drain of the first P-type transistor, the second drain is connected to the I/O pad, the second body region receives the first control signal,
wherein, when the I/O pad operates in the input mode, a change of a voltage of the first gate of the first P-type transistor and a change of a voltage of the second gate of the second P-type transistor are synchronized with a change of a voltage of the first body region of the first P-type transistor and a change of a voltage of the second body region of the second P-type transistor, and when the pad voltage is lower than or equal to the supply voltage the I/O pad operates in the normal input mode of the input mode, and when the pad voltage is higher than the supply voltage the I/O pad operates in the tolerance mode of the input mode, a voltage of the first control signal is equal to the pad voltage.