Low leakage power switch

Patent metadata

Field	Value
Publication number	US-2019097622-A1
Application number	US-201715717276-A
Country	US
Kind code	A1
Filing date	Sep 27, 2017
Priority date	Sep 27, 2017
Publication date	Mar 28, 2019
Grant date	—

Abstract

A power switch control circuit is disclosed. A sensor circuit may determine a leakage current of a power switch coupled to a power supply signal and a power terminal of a circuit block. The power switch may be configured to selectively couple or decouple the circuit block from the power supply signal using a switch control signal. The switch control circuit may, in response to receiving a request to open the power switch, determine a target voltage level that is greater than a voltage level of the power supply signal for the switch control signal using the leakage current, and transition the switch control signal from an initial voltage to the target voltage level.

First claim

What is claimed is:

1 . An, apparatus, comprising:
a circuit block; a power switch coupled to a power terminal of the circuit block and a power supply signal, wherein the power switch is configured to selectively couple or decouple the circuit block from the power supply signal using a switch control signal; a sensor circuit configured to determine a leakage current of the power switch; and a switch control circuit configured to:
receive a first request to open the power switch;
in response to receiving the first request:
determine a first target voltage level, greater than a voltage level of the power supply signal, for the switch control signal using the leakage current; and
transition a voltage level of the switch control signal from an initial voltage to the first target voltage level.

2 . The apparatus of claim 1 , wherein the sensor circuit is further configured to determine a resistance of the power switch, and wherein the switch control circuit is further configured to:
receive a second request to close the power switch; in response to receiving the second request:
determine a second target voltage level, less than a ground voltage level, for the switch control signal based on the resistance; and
transition the voltage level of the switch control signal from the first target voltage level to the second target voltage level.

3 . The apparatus of claim 2 , wherein the sensor circuit is further configured to measure a rate of change of the switch control signal, and wherein the switch control circuit is further configured to transition the voltage level of the switch control signal from the first target voltage level to the second target voltage level using data indicative of the rate of change of the switch control signal.

4 . The apparatus of claim 1 , wherein the sensor circuit is further configured to compare the voltage level of the switch control signal to a maximum voltage level.

5 . The apparatus of claim 1 , wherein to determine the leakage current of the power switch, the sensor circuit is further configured to measure a leakage current of a replica circuit.

6 . The apparatus of claim 1 , wherein the power switch includes at least one buffer circuit configured to generate a buffered version of the switch control signal.

7 . A method, comprising:
receiving, by a switch control circuit, a first request to open a power switch coupled to a power supply signal and a power terminal of a circuit block; selectively coupling or decoupling the circuit block and the power supply signal by the power switch using a switch control signal; determining, by a sensor circuit, a leakage current of the power switch; in response to receiving the first request:
determining a first target voltage level, greater than a voltage level of the power supply signal, for the switch control signal using the leakage current; and
transitioning a voltage level of the switch control signal from an initial voltage to the first target voltage level.

8 . The method of claim 7 , further comprising:
determining, by the sensor circuit, a resistance of the power switch; receiving a second request to close the power switch; in response to receiving the second request:
determining a second target voltage level, less than a ground voltage level, for the switch control signal based on the resistance; and
transitioning the voltage level of the switch control signal from the first target voltage level to the second target voltage level.

9 . The method of claim 8 , further comprising, measuring, by the sensor circuit, a rate of change of the switch control signal, and transitioning the voltage level of the switch control signal from the first target voltage level to the second target voltage level using data indicative of the rate of change of the switch control signal.

10 . The method of claim 7 , further comprising, comparing, by the sensor circuit, the voltage level of the switch control signal to a maximum voltage level.

11 . The method of claim 7 , wherein determining, by the sensor circuit, the leakage current of the power switch, includes measuring a leakage current of a replica circuit.

12 . The method of claim 7 , further comprising, measuring, by the sensor circuit, a temperature of the power switch.

13 . The method of claim 7 , further comprising, buffering the switch control signal by a buffer circuit.

14 . A system, comprising:
a power management unit configured to generate an internal power supply signal using an external power supply signal; a processor; a power switch coupled to a power terminal of the processor and the internal power supply signal, wherein the power switch is configured to selectively couple or decouple the processor from the internal power supply signal using a switch control signal; a sensor circuit configured to determine a leakage current of the power switch; and a switch control circuit configured to:
receive a first request to open the power switch;
in response to receiving the first request:
determine a first target voltage level, greater than a voltage level of the internal power supply signal, for the switch control signal using the leakage current; and
transition a voltage level of the switch control signal from an initial voltage to the first target voltage level.

15 . The system of claim 14 , wherein the sensor circuit is further configured to determine a resistance of the power switch, and wherein the switch control circuit is further configured to:
receive a second request to close the power switch; in response to receiving the second request:
determine a second target voltage level, less than a ground voltage level, for the switch control signal based on the resistance; and
transition the voltage level of the switch control signal from the first target voltage level to the second target voltage level.

16 . The system of claim 15 , wherein the sensor circuit is further configured to measure a rate of change of the switch control signal, and wherein the switch control circuit is further configured to transition the voltage level of the switch control signal from the first target voltage level to the second target voltage level using data indicative of the rate of change of the switch control signal.

17 . The system of claim 14 , wherein the sensor circuit is further configured to compare the voltage level of the switch control signal to a maximum voltage level.

18 . The system of claim 14 , wherein to determine the leakage current of the power switch, the sensor circuit is further configured to measure a leakage current of a replica circuit.

19 . The system of claim 14 , wherein the sensor circuit is further configured to measure a temperature of the power switch.

20 . The system of claim 14 , wherein the power switch includes at least on buffer circuit configured to generate a buffered version of the switch control signal.

Assignees

• Apple Inc

Inventors

• Raszka Jaroslav
• Barn Amrinder S
• Zyuban Victor
• Suzuki Shingo
• Bhatia Ajay Kumar
• Abu-Rahma Mohamed H
• Nazar Shahzad
• Hess Greg M

Classifications

• H03K17/162 Primary

  without feedback from the output circuit to the control circuit · CPC title

• H03K2217/0027

  Measuring means of, e.g. currents through or voltages across the switch · CPC title

• H03K19/00369

  Modifications for compensating variations of temperature, supply voltage or other physical parameters · CPC title

• H03K2217/0036

  Means reducing energy consumption · CPC title

• H03K19/0016

  by using a control or a clock signal, e.g. in order to apply power supply · CPC title