Integrated circuit charge pump with failure protection

Patent metadata

Field	Value
Publication number	US-9819260-B2
Application number	US-201514597538-A
Country	US
Kind code	B2
Filing date	Jan 15, 2015
Priority date	Jan 15, 2015
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

Disclosed is a charge pump protection device including a power supply voltage, a charge pump to produce an output voltage higher than the power supply voltage, the charge pump including, a pumping capacitor to store voltage during a charging state and to discharge the voltage during a pumping state thereof, a plurality of switches to regulate the charging and pumping states, a charge pump capacitor to store the output voltage, and at least one current limiter in series with at least one of the plurality of switches to limit current and prevent an electrical failure of the charge pump.

First claim

The invention claimed is:

1. A charge pump protection device comprising:
a power supply configured to produce a power supply voltage;
a charge pump configured to produce an output voltage that is substantially equal to the power supply voltage plus a second voltage lower than the power supply voltage, the charge pump including:
a second charge pump configured to produce the second voltage lower than the power supply voltage;
a pumping capacitor configured to store charge during a charging state and to discharge the charge during a pumping state thereof;
a plurality of switches configured to regulate the charging and pumping states;
a charge pump capacitor configured to store the output charge; and
at least one current limiter in series with at least one of the plurality of switches configured to limit current and prevent an electrical failure of the charge pump.

2. The device of claim 1 , wherein the second voltage is superimposed on a pumping capacitor voltage to produce the output voltage.

3. The device of claim 1 , wherein a pumping capacitor voltage is superimposed on the second voltage to produce the output voltage.

4. The device of claim 1 , wherein the second charge pump circuit includes a Dickson charge pump.

5. The device of claim 1 , wherein the charge pump protection circuit protects a first terminal of the pumping capacitor.

6. The device of claim 1 , wherein the at least one current limiter includes a first current limiter in series with a first switch to protect the pumping capacitor node during a charging cycle.

7. The device of claim 6 , wherein the first current limiter includes a MOS current mirror.

8. The device of claim 1 , wherein the at least one current limiter includes a second current limiter in series with a second switch to protect the pumping capacitor node during a pumping cycle.

9. The device of claim 1 , comprising a terminal of the pumping capacitor between the pumping capacitor and the charge pump capacitor and an electrical element to limit the current flow.

10. The device of claim 9 , wherein the electrical element is a diode.

11. The device of claim 9 , wherein the electrical element is a MOS transistor switch.

12. The device of claim 1 , wherein voltage stored in the charge pump capacitor is used to power a high-side gate driver of a class D audio amplifier.

13. The device of claim 1 , comprising a clock circuit to control timing within the charge pump detection circuit.

14. A charge pump detection device comprising:
a power supply configured to produce a power supply voltage;
a charge pump configured to produce an output voltage that is substantially equal to the power supply voltage plus a second voltage lower than the power supply voltage, a second charge pump configured to produce the second voltage lower than the power supply voltage, the charge pump including a pumping capacitor to store voltage during a charging state and discharge the voltage during a pumping state; and
a start-up protection circuit configured to protect a terminal of the charge pump capacitor during a start-up event including a current limiter positioned between the power supply and the terminal of the charge pump capacitor to limit current and prevent electrical overstress.

15. The device of claim 14 , wherein the start-up protection circuit includes a MOS transistor that is open at the beginning of a clock cycle.

16. The device of claim 15 , wherein when it is determined that the output voltage exceeds the power supply voltage, the MOS transistor is closed and the start-up protection circuit is bypassed.

17. The device of claim 14 , wherein the start-up protection circuit comprises a current mirror.

18. The device of claim 1 , wherein the start-up protection circuit is activated when the output voltage is determined not higher than the power supply voltage.

Assignees

• Nxp Bv

Inventors

• Hissink Derk Jan
• Sneep Jacobus Govert
• Mostert Fred
• Van Iersel Hendrikus

Classifications

• H02M3/07

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H03F3/185

  with field-effect devices (H03F3/187 takes precedence) · CPC title

• H02M3/073 Primary

  Charge pumps of the Schenkel-type · CPC title

• H03F1/523

  for amplifiers using field-effect devices (H03F1/526 takes precedence) · CPC title

• H03K2217/0081

  Power supply means, e.g. to the switch driver · CPC title