US 11,791,801 B2
Impedance control circuit capable of confirming connection status
Ya-Hsuan Sung, HsinChu (TW)
Assigned to Realtek Semiconductor Corp., HsinChu (TW)
Filed by Realtek Semiconductor Corp., HsinChu (TW)
Filed on Apr. 11, 2022, as Appl. No. 17/717,167.
Claims priority of application No. 110113562 (TW), filed on Apr. 15, 2021.
Prior Publication US 2022/0337227 A1, Oct. 20, 2022
Int. Cl. H03H 11/28 (2006.01)
CPC H03H 11/28 (2013.01) 9 Claims
OG exemplary drawing
 
1. An impedance control circuit comprising:
a configuration channel interface coupled to a first universal serial bus device;
a first resistor having a first terminal coupled to the configuration channel interface, and a second terminal;
a first transistor having a first terminal coupled to the second terminal of the first resistor, a second terminal coupled to a system voltage terminal, and a control terminal, wherein the first transistor has a negative threshold voltage;
a second transistor having a first terminal coupled to the second terminal of the first resistor, a second terminal coupled to the system voltage terminal, and a control terminal, wherein the second transistor has a positive threshold voltage;
a second resistor having a first terminal coupled to the second terminal of the first resistor, and a second terminal coupled to the control terminal of the second transistor; and
a third resistor having a first terminal coupled to the second terminal of the second resistor, and a second terminal coupled to the system voltage terminal.