Power supply circuit with reduced leakage current

1. An apparatus, comprising:

a switch circuit configured to power a circuit block;

a delay circuit configured

to delay enabling the switch circuit powering the circuit block and

to be powered down;

a bypass circuit configured to bypass the delay circuit to disable the switch circuit powering the circuit block,

the bypass circuit comprising a first input and a second input,

the delay circuit configured to delay enabling the switch circuit powering the circuit block via the first input, and

the bypass circuit further configured to, based on signaling received via the second input, bypass the delay circuit to disable the switch circuit powering the circuit block; and

a control circuit configured to, based on a first control signal and a second control signal, provide the signaling to the second input to bypass the delay circuit to disable the switch circuit powering the circuit block,

the control circuit comprising a voltage shifter circuit and configured to provide the signaling to the second input via the voltage shifter circuit.

2. The apparatus of claim 1 , the bypass circuit comprising a gate coupled to the first input and to the second input.

3. The apparatus of claim 1 , the control circuit further configured to power down the delay circuit based on the first control signal and the second control signal.

4. The apparatus of claim 3 , the control circuit further comprising a voltage shifter circuit; the control circuit further configured to power down the delay circuit via the voltage shifter circuit.

5. The apparatus of claim 1 , the first control signal being in a first voltage domain having a first supply voltage, the second control signal being in a second voltage domain having a second supply voltage different from the first supply voltage.

6. The apparatus of claim 1 , the control circuit further configured to provide the signaling to the second input to bypass the delay circuit to disable the switch circuit powering the circuit block, in response to the second control signal being asserted and independent of the first control signal.

7. The apparatus of claim 6 , the control circuit further configured to power down the delay circuit, in response to the second control signal being asserted and independent of the first control signal.

8. The apparatus of claim 7 , the control circuit further configured to enable the switch circuit powering the circuit block via the delay circuit, in response to the second control signal being not asserted and based on the first control signal.

9. The apparatus of claim 8 , the control circuit further configured

to provide the signaling on the second input to bypass the delay circuit to disable the switch circuit powering the circuit block and

to power down the delay circuit, in response to the second control signal being not asserted and based on the first control signal.

10. The apparatus of claim 6 , the first control signal being in a first voltage domain having a first supply voltage, the second control signal being in a second voltage domain having a second supply voltage different from the first supply voltage.

11. The apparatus of claim 10 , the second control signal being asserted in response to powering up the second supply voltage.

12. The apparatus of claim 1 , comprising:

a second switch circuit configured to power a second circuit block;

a second delay circuit configured

to delay enabling the second switch circuit powering the second circuit block conditioned on the switch circuit powering the circuit block and

to be powered down;

a second bypass circuit configured to bypass the second delay circuit to disable the second switch circuit powering the second circuit block.

13. The apparatus of claim 1 , comprising a device selected from one of a computing system, a mobile computing system, an Internet of Things device, a virtual reality system, or an augmented reality system, the device incorporating the switch circuit, the circuit block, the bypass circuit, and the delay circuit.

14. A method to reduce leakage current, comprising:

powering, by a switch circuit, a circuit block;

powering down a delay circuit;

bypassing, by a bypass circuit, the delay circuit to disable the switch circuit powering the circuit block;

delaying, by the delay circuit via a first input of the bypass circuit, enabling the switch circuit powering the circuit block;

bypassing, by the bypass circuit, the delay circuit to disable the switch circuit powering the circuit block based on signaling received via a second input of the bypass circuit;

providing, by a control circuit, the signaling on the second input to bypass the delay circuit to disable the switch circuit powering the circuit block, based on a first control signal and a second control signal; and

providing the signaling on the second input via a voltage shifter circuit of the control circuit.

15. The method of claim 14 , the bypass circuit comprising a gate coupled to the first input and to the second input.

16. The method of claim 14 , further comprising

powering down, by the control circuit, the delay circuit based on the first control signal and the second control signal.

17. The method of claim 16 , further comprising

powering down, by the control circuit, the delay circuit via a voltage shifter circuit of the control circuit.

18. The method of claim 14 , the first control signal being in a first voltage domain having a first supply voltage, the second control signal being in a second voltage domain having a second supply voltage different from the first supply voltage.

19. The method of claim 14 , further comprising

providing, by the control circuit, the signaling on the second input to bypass the delay circuit to disable the switch circuit powering the circuit block, in response to the second control signal being asserted and independent of the first control signal.

20. The method of claim 19 , further comprising

powering down, by the control circuit in response to the second control signal being asserted and independent of the first control signal, the delay circuit.

21. The method of claim 20 , further comprising

enabling, by the control circuit in response to the second control signal being not asserted and based on the first control signal, the switch circuit powering the circuit block via the delay circuit.

22. The method of claim 21 , further comprising

providing, by the control circuit in response to the second control signal being not asserted and based on the first control signal, the signaling on the second input to the bypass circuit to bypass the delay circuit to disable the switch circuit powering the circuit block; and

powering down, by the control circuit in response to the second control signal being not asserted and based on the first control signal, the delay circuit.

23. The method of claim 19 , the first control signal being in a first voltage domain having a first supply voltage, the second control signal being in a second voltage domain having a second supply voltage different from the first supply voltage.

24. The method of claim 23 , the second control signal being asserted in response to powering up the second supply voltage.

25. The method of claim 14 , comprising:

powering, by a second switch circuit, a second circuit block;

delaying, by a second delay circuit conditioned on the switch circuit powering the circuit block, enabling the second switch circuit powering the second circuit block;

powering down the second delay circuit;

bypassing, by a second bypass circuit, the second delay circuit to disable the second switch circuit powering the second circuit block.