Usb-pd supply interface and associated method

Abstract

An embodiment of the present disclosure relates to a power supply interface comprising: a converter delivering a first DC voltage; a resistor connected between the converter and an output terminal of the interface delivering a second DC voltage; a first circuit delivering a second signal representative of a difference between the second DC voltage and a voltage threshold when a first signal is in a first state, and at a default value otherwise; a second circuit delivering a third signal representative of a value of a current in first resistor multiplied by a gain of the third circuit, and modifying the gain based on the second signal; and a third circuit configured to deliver a signal for controlling the converter based at least on the third signal.

What is claimed is: 
     
         1 . A power supply interface comprising:
 a converter having a power supply voltage input, and a first direct current (DC) voltage terminal;   a first resistor and a first switch coupled in series between the first DC voltage terminal and a second DC voltage output terminal of the power supply interface;   a first circuit comprising:
 a second resistor and a second switch connected in parallel, wherein a control terminal of the second switch is coupled to a bypass output of a fourth circuit; 
 an fifth circuit having a first input coupled to an internal power supply potential, a second input coupled to a current-control output, and an output coupled to the second resistor, the second switch, and a sixth circuit; and 
 the sixth circuit, having a first input coupled to the fifth circuit, a second input coupled to a voltage threshold, and a modify output coupled to a second circuit; 
   the second circuit, comprising:
 a first operational amplifier; 
 a third resistor coupled between a first terminal of the first resistor coupled to the converter and a first input of the first operational amplifier, a second input of the first operational amplifier being coupled to a second terminal of the first resistor coupled to the second DC voltage output terminal of the power supply interface; 
 a first transistor, a fifth resistor and a sixth resistor series-connected between the first input of the first operational amplifier and a ground; and 
 a second transistor having conduction terminals connected in parallel with the sixth resistor and having a control terminal coupled to the modify output of the sixth circuit; 
 wherein the first transistor has a control terminal coupled to an output of the first operational amplifier, a first conduction terminal coupled to the first input of the first operational amplifier, and a second conduction terminal coupled to the fifth resistor; and 
   a third circuit comprising:
 a second operational amplifier having a first input coupled to the second conduction terminal of the first transistor, a second input coupled to a negotiated current threshold signal, and the current-control output; 
 a fourth resistor coupled between a first negotiated target voltage signal of the second DC voltage output terminal, and a first input of a third operational amplifier; 
 a third transistor having conduction terminals coupled between the first input of the third operational amplifier and the ground, wherein a control terminal of the third transistor is coupled to the current-control output of the second operational amplifier; and 
 the third operational amplifier, having a second input coupled to a voltage divider coupled between the second DC voltage output terminal and the ground, and an output coupled to a control input of the converter. 
   
     
     
         2 . The power supply interface according to  claim 1 , wherein the modify output of the sixth circuit is representative of a difference between the second DC voltage output terminal and the voltage threshold in response to the bypass output being in an off state, and a default value in response to the bypass output being in an on state. 
     
     
         3 . The power supply interface according to  claim 1 , wherein the first input to the second operational amplifier is representative of a value of a first current in the first resistor multiplied by a gain of the second circuit, where the gain is modified based on the modify output. 
     
     
         4 . The power supply interface according to  claim 1 , wherein the output of the third operational amplifier is configured to control the converter based on the negotiated current threshold signal, on the first negotiated target voltage signal, on a current value of the second DC voltage output terminal, and on the modify output. 
     
     
         5 . The power supply interface according to  claim 1 , further comprising the fourth circuit configured to deliver the bypass output in an off state for a predetermined time period after the second DC voltage output terminal reaches the voltage threshold and/or when a temperature in the power supply interface is lower than a maximum temperature. 
     
     
         6 . The power supply interface according to  claim 5 , wherein the fourth circuit comprises:
 a counter configured to count during the predetermined time period after a switching of a starting signal for starting the counter, and to switch an output signal of the counter once the predetermined time period has elapsed; and
 a first comparator of a signal representative of the voltage threshold and of a signal representative of a current value of the second DC voltage output terminal, configured to deliver the starting signal; and/or 
 a second comparator configured to deliver a signal representative of a comparison of a signal representative of the maximum temperature and of a signal representative of the temperature in the power supply interface, 
   wherein the bypass output is determined from the output signal of the counter and/or from the signal representative of the comparison.   
     
     
         7 . The power supply interface according to  claim 1 , intended to power a load, the power supply interface being configured to negotiate a power to be delivered to the load, selectable from a predefined list of powers, a negotiated power determining the negotiated current threshold signal, the first negotiated target voltage signal, and the voltage threshold. 
     
     
         8 . The power supply interface according to  claim 7 , further comprising the fourth circuit configured to deliver the bypass output in an off state for a predetermined time period after the second DC voltage output terminal reaches the voltage threshold and/or when a temperature in the power supply interface is lower than a maximum temperature,
 wherein the negotiated power also determines the predetermined time period and/or the maximum temperature.   
     
     
         9 . The power supply interface according to  claim 1 , wherein the first, second, and third circuits are configured so that, when the bypass output is in an off state, a control signal at the control input of the converter is such that a current value of the second DC voltage output terminal remains greater than or equal to the voltage threshold. 
     
     
         10 . The power supply interface according to  claim 1 , wherein the control terminal of the first transistor is directly connected to the output of the first operational amplifier. 
     
     
         11 . The power supply interface according to  claim 1 , wherein the first conduction terminal is directly connected to the first input of the first operational amplifier. 
     
     
         12 . A power supply interface comprising:
 a converter having a power supply voltage input, and a first direct current (DC) voltage terminal;   a first resistor and a first switch coupled in series between the first DC voltage terminal and a second DC voltage output terminal of the power supply interface;   a second resistor and a second switch connected in parallel, wherein a control terminal of the second switch is coupled to a bypass output;   a first circuit having a first input coupled to an internal power supply potential, a second input coupled to a current-control output, and an output coupled to the second resistor, the second switch, and a first operational amplifier;   the first operational amplifier, having a first input coupled to the first circuit, a second input coupled to a voltage threshold, and a modify output coupled to a second transistor;   a second operational amplifier;   a third resistor coupled between a first terminal of the first resistor coupled to the converter and a first input of the second operational amplifier, a second input of the second operational amplifier being coupled to a second terminal of the first resistor coupled to the second DC voltage output terminal of the power supply interface;   a first transistor, a fifth resistor and a sixth resistor series-connected between the first input of the second operational amplifier and a ground;   the second transistor, having conduction terminals connected in parallel with the sixth resistor and having a control terminal coupled to the modify output of the first operational amplifier;   wherein the first transistor has a control terminal coupled to an output of the second operational amplifier, a first conduction terminal coupled to the first input of the second operational amplifier, and a second conduction terminal coupled to the fifth resistor; and   a third operational amplifier having a first input coupled to the second conduction terminal of the first transistor, a second input coupled to a negotiated current threshold signal, and the current-control output;   a fourth resistor coupled between a first negotiated target voltage signal of the second DC voltage output terminal, and a first input of a fourth operational amplifier;   a third transistor having conduction terminals coupled between the first input of the fourth operational amplifier and the ground, wherein a control terminal of the third transistor is coupled to the current-control output of the third operational amplifier; and   the fourth operational amplifier, having a second input coupled to a voltage divider coupled between the second DC voltage output terminal and the ground, and an output coupled to a control input of the converter.   
     
     
         13 . The power supply interface according to  claim 12 , wherein the modify output of the first operational amplifier is representative of a difference between the second DC voltage output terminal and the voltage threshold in response to the bypass output being in an off state, and a default value in response to the bypass output being in an on state. 
     
     
         14 . The power supply interface according to  claim 12 , wherein the first input to the third operational amplifier is representative of a value of a first current in the first resistor multiplied by a gain of the second operational amplifier as modified by the modify output. 
     
     
         15 . The power supply interface according to  claim 12 , wherein the output of the fourth operational amplifier is configured to control the converter based on the negotiated current threshold signal, on the first negotiated target voltage signal, on a current value of the second DC voltage output terminal, and on the modify output. 
     
     
         16 . The power supply interface according to  claim 12 , further comprising a fourth circuit configured to deliver the bypass output in an off state for a predetermined time period after the second DC voltage output terminal reaches the voltage threshold and/or when a temperature in the power supply interface is lower than a maximum temperature. 
     
     
         17 . The power supply interface according to  claim 16 , wherein the fourth circuit comprises:
 a counter configured to count during the predetermined time period after a switching of a starting signal for starting the counter, and to switch an output signal of the counter once the predetermined time period has elapsed; and
 a first comparator of a signal representative of the voltage threshold and of a signal representative of a current value of the second DC voltage output terminal, configured to deliver the starting signal; and/or 
 a second comparator configured to deliver a signal representative of a comparison of a signal representative of the maximum temperature and of a signal representative of the temperature in the power supply interface, 
   wherein the bypass output is determined from the output signal of the counter and/or from the signal representative of the comparison.   
     
     
         18 . The power supply interface according to  claim 12 , intended to power a load, the power supply interface being configured to negotiate a power to be delivered to the load, selectable from a predefined list of powers, a negotiated power determining the negotiated current threshold signal, the first negotiated target voltage signal, and the voltage threshold. 
     
     
         19 . The power supply interface according to  claim 18 , further comprising a fourth circuit configured to deliver the bypass output in an off state for a predetermined time period after the second DC voltage output terminal reaches the voltage threshold and/or when a temperature in the power supply interface is lower than a maximum temperature,
 wherein the negotiated power also determines the predetermined time period and/or the maximum temperature.   
     
     
         20 . The power supply interface according to  claim 12 , wherein the power supply interface is configured so that, when the bypass output is in an off state, a control signal at the control input of the converter is such that a current value of the second DC voltage output terminal remains greater than or equal to the voltage threshold.