Voltage supply regulator with overshoot protection

Patent metadata

Field	Value
Publication number	US-9846445-B2
Application number	US-201615134512-A
Country	US
Kind code	B2
Filing date	Apr 21, 2016
Priority date	Apr 21, 2016
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A voltage supply regulator includes a first output resistor including a first terminal coupled to an output voltage of the voltage supply regulator and a second terminal; a first comparator including a first input coupled to a reference voltage, a second input coupled to the second terminal of the first output resistor, and an output coupled to a base of a first regulator transistor; a current mirror coupled to a collector of the first regulator transistor; and an slew rate detector coupled to the current mirror that includes a first terminal coupled to control electrodes of first and second transistors in the current mirror, and a detection bipolar junction transistor having a collector coupled to the control electrodes of the first and second transistors in the current mirror, and a base coupled to a second terminal of the capacitor.

First claim

What is claimed is:

1. A voltage supply regulator, comprising:
a first output resistor including a first terminal coupled to an output voltage of the voltage supply regulator and a second terminal;
a first opamp including a first input coupled to a reference voltage, a second input coupled to the second terminal of the first output resistor, and an output coupled to a base of a first regulator transistor;
a current mirror coupled to a collector of the first regulator transistor;
a slew rate detector coupled to the current mirror, wherein the slew rate detector includes:
a capacitor including a first terminal coupled to control electrodes of first and second transistors in the current mirror; and
a detection bipolar junction transistor including a collector coupled to the control electrodes of the first and second transistors in the current mirror, and a base coupled to a second terminal of the capacitor.

2. The voltage supply regulator of claim 1 , further comprising:
a second output resistor coupled in series with the first output resistor; and
a third output resistor coupled in series with the second output resistor.

3. The voltage supply regulator of claim 2 , further comprising:
a first comparator including a first input coupled to the reference voltage and a second input coupled to a junction between the second and third resistors.

4. The voltage supply regulator of claim 3 , further comprising:
a second regulator transistor including a control electrode coupled to an output of the first comparator, a first current electrode coupled to the output voltage, and a second current electrode coupled to ground.

5. The voltage supply regulator of claim 2 , further comprising:
a first current electrode of the second transistor of the current mirror is coupled to an input voltage; and
the collector of the first regulator transistor is coupled to the current mirror at a second current electrode of the second transistor of the current mirror.

6. The voltage supply regulator of claim 2 , further comprising:
an emitter of the first regulator transistor coupled to ground at an output terminal of the third resistor.

7. The voltage supply regulator of claim 1 , the slew rate detector further comprising:
a first diode and a second diode,
the first diode having an input terminal coupled to the second terminal of the capacitor and an output terminal coupled to an input terminal of the second diode, and
an output terminal of the second diode is coupled to the input terminal of the first diode and the second terminal of the capacitor.

8. A voltage supply regulator, comprising:
a current mirror coupled to receive an input voltage, the current mirror including:
a first transistor having a first current electrode coupled to the input voltage, a second current electrode coupled to a first terminal of a current source, and a gate electrode coupled to the second electrode;
a second transistor having a first current electrode coupled to the input voltage, a second current electrode, and a gate electrode coupled to the gate electrode of the first transistor;

a comparator;
a first regulator transistor including a first current electrode, a second current electrode coupled to ground, and a gate electrode coupled to an output of the comparator;
an opamp;
a resistor divider;
a second regulator transistor including a base coupled to an output of the opamp, a collector coupled to the second current electrode of the second transistor, and an emitter coupled to an ending terminal of the resistor divider;
a slew rate detector including:
a capacitor including a first terminal coupled to the gate electrodes of the first and second transistors;
a bipolar junction transistor including a collector coupled to the gate electrodes of the first and second transistors and a base coupled to a second terminal of the capacitor.

9. The voltage supply regulator of claim 8 , further comprising:
a pass transistor including a first current electrode coupled to the input voltage and the first current electrodes of the first and second transistors, a second current electrode coupled to a beginning terminal of the resistor divider and to provide a regulated output voltage, and a gate electrode coupled to the second electrode of the second transistor and the collector of the second regulator transistor.

10. The voltage supply regulator of claim 9 , wherein:
the resistor divider includes a plurality of resistors coupled in series between the beginning terminal and the ending terminal;
the opamp includes a first input coupled to a reference voltage and a second input coupled between a first and a second one of the plurality of resistors.

11. The voltage supply regulator of claim 10 , wherein the comparator includes a first input coupled to the reference voltage and a second input coupled between the second one of the plurality of resistors and a third one of the plurality of resistors.

12. The voltage supply regulator of claim 11 , wherein the first regulator transistor is an NMOS transistor.

13. The voltage supply regulator of claim 11 , wherein a resistance of the second one of the plurality of resistors is between 6 and 15 percent of a resistance of the third one of the plurality of resistors.

14. The voltage supply regulator of claim 8 , wherein the slew rate detector includes a first diode and a second diode,
the first diode having an input terminal coupled to the second terminal of the capacitor and an output terminal coupled to an input terminal of the second diode, and
an output terminal of the second diode is coupled to the input terminal of the first diode and the second terminal of the capacitor.

15. The voltage supply regulator of claim 8 , wherein the first, second, and pass transistors are PMOS transistors.

16. The voltage supply regulator of claim 8 , wherein the second regulator transistor is an NPN bipolar junction transistor.

17. A voltage supply regulator, comprising:
a slew rate detector between control electrodes of two transistors in a current mirror, wherein inputs to the current mirror are coupled to an input voltage (VIN) and the slew rate detector includes:
a pair of diodes coupled back-to-back with one another;
a capacitor ( 18 ) including a first terminal coupled to the control electrodes of the two transistors in the current mirror, and a second terminal coupled to a first terminal of the pair of diodes;
a detection bipolar junction transistor including a collector coupled to the control electrodes of the first and second transistors in the current mirror, a base coupled to a second terminal of the capacitor and the first terminal of the pair of diodes, and an emitter coupled to a second terminal of the pair of diodes;

a current source coupled to a second current electrode of a first of the two transistors in the current mirror;
first, second and third resistors coupled in series;
a first regulator transistor having a collector coupled to a second current electrode of a second one of the two transistors of the current mirror, a base coupled to an output of a first opamp, and an emitter coupled to an output terminal of the third resistor.

18. The voltage supply regulator of claim 17 , further comprising:
a pass transistor having:
a first current electrode coupled to respective first current electrodes of the two transistors of the current mirror and the input voltage,
a control electrode coupled to the second current electrode of the second one of the two transistors of the current mirror, and
a second current electro

Assignees

• Freescale Semiconductor Inc
• Nxp Usa Inc

Inventors

• Pigott John M
• Mayega Valerian
• Yip Hang Fung

Classifications

• G05F1/575

  characterised by the feedback circuit · CPC title

• G05F1/562

  with a threshold detection shunting the control path of the final control device · CPC title

• G05F1/569

  for protection · CPC title

• G05F1/571 Primary

  with overvoltage detector · CPC title