US 12,444,922 B2
Power supply circuit having protection circuit against electrostatic discharge stress and semiconductor device having the power supply circuit
Tatsuhiko Maruyama, Kawasaki Kanagawa (JP); and Toyoaki Uo, Yokohama Kanagawa (JP)
Assigned to Kabushiki Kaisha Toshiba, Kawasaki (JP); and Toshiba Electronic Devices & Storage Corporation, Kawasaki (JP)
Filed by Kabushiki Kaisha Toshiba, Tokyo (JP); and Toshiba Electronic Devices & Storage Corporation, Tokyo (JP)
Filed on Aug. 26, 2022, as Appl. No. 17/896,647.
Claims priority of application No. 2021-184206 (JP), filed on Nov. 11, 2021.
Prior Publication US 2023/0146002 A1, May 11, 2023
Int. Cl. H02H 3/22 (2006.01)
CPC H02H 3/22 (2013.01) 10 Claims
OG exemplary drawing
 
1. A power supply circuit comprising:
a first transistor connected between an input terminal and an output terminal;
a feedback voltage generation circuit configured to divide an output voltage to generate a feedback voltage;
a first voltage generation circuit configured to supply a voltage to a first control terminal of the first transistor via a first node based on the feedback voltage and a reference voltage; and
a protection circuit configured to, when an input voltage increases above a first threshold voltage within a predetermined time, output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value, to the first control terminal,
wherein the protection circuit includes
a second transistor connected between the input terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a first capacitor connected between the input terminal and a second node,
a first resistor connected between the second node and a ground terminal,
a third transistor with a third control terminal connected to the second node, connected between the ground terminal and a third node, and
a second resistor connected between the input terminal and the third node, and wherein
the third node is connected to the second control terminal of the second transistor.
 
6. A semiconductor device that modulates a logic signal input to a signal input terminal and outputs a demodulated logic signal from a signal output terminal, comprising a power supply circuit configured to supply an output voltage used for driving the semiconductor device, wherein the power supply circuit includes
a first transistor connected between an input terminal and an output terminal,
a feedback voltage generation circuit configured to divide the output voltage to generate a feedback voltage,
a first voltage generation circuit configured to supply a voltage to a first control terminal of the first transistor via a first node based on the feedback voltage and a reference voltage, and
a protection circuit configured to, when an input voltage increases above a first threshold voltage within a predetermined time, output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value, to the first control terminal,
wherein the protection circuit includes
a second transistor connected between the input terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a first capacitor connected between the input terminal and a second node,
a first resistor connected between the second node and a ground terminal,
a third transistor with a third control terminal connected to the second node, connected between the ground terminal and a third node, and
a second resistor connected between the input terminal and the third node, and wherein
the third node is connected to the second control terminal of the second transistor.
 
7. A power supply circuit supplying an output voltage between a first terminal and a second terminal, comprising:
a first transistor connected between a third terminal inputting an input voltage and the first terminal outputting the output voltage;
an electrostatic protection circuit connected between the third terminal and the second terminal, and configured to electrically conduct between the third terminal and the second terminal when a voltage between the third terminal and the second terminal exceeds a predetermined voltage; and
a protection circuit configured to output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value to a first control terminal of the first transistor via a first node, when the input voltage increases above a first threshold voltage within a predetermined time,
wherein the first threshold voltage is set to be lower than the predetermined voltage,
wherein the protection circuit includes
a second transistor connected between the third terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a first capacitor connected between the third terminal and a second node,
a first resistor connected between the second node and the second terminal,
a third transistor with a third control terminal connected to the second node, connected between the second terminal and a third node, and
a second resistor connected between the third terminal and the third node, and wherein
the third node is connected to the second control terminal of the second transistor.
 
10. A power supply circuit supplying an output voltage between a first terminal and a second terminal, comprising:
a first transistor connected between a third terminal inputting an input voltage and the first terminal outputting the output voltage;
an electrostatic protection circuit connected between the third terminal and the second terminal, and configured to electrically conduct between the third terminal and the second terminal when a voltage between the third terminal and the second terminal exceeds a predetermined voltage; and
a protection circuit configured to output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value to a first control terminal of the first transistor via a first node, when the input voltage increases above a first threshold voltage within a predetermined time,
wherein the first threshold voltage is set to be lower than the predetermined voltage,
wherein the protection circuit includes
a second transistor connected between the third terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a third resistor connected between the third terminal and a fourth node, and
a second capacitor connected between the fourth node and the second terminal, and wherein
the fourth node is connected to the second control terminal of the second transistor.