Multi-phase turn-on blanking time with VBATT-based fault threshold voltage

Patent metadata

Field	Value
Publication number	US-9733296-B2
Application number	US-201514946405-A
Country	US
Kind code	B2
Filing date	Nov 19, 2015
Priority date	Nov 19, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A low-side (LS) output pre-driver has a short-circuit-to-battery fault detection scheme for a MOSFET switch having a drain connection to a load connected to a battery voltage and a source connection tied to ground. The LS output pre-driver includes a comparator, a reference voltage selector, a multi-phase blank/filter, a multi-phase control timer. The first signal of the multi-phase control timer instructs the reference voltage selector to select which of the plurality of reference voltage signals is provided to the second input of the comparator. The second signal of the multi-phase control timer instructs the multi-phase blank/filter to change from one of the plurality of time intervals to another of the plurality of time intervals.

First claim

What is claimed is:

1. A low-side (LS) output pre-driver having a short-circuit-to-battery fault detection scheme for a MOSFET switch having a drain connection to a load connected to a battery voltage and a source connection tied to ground, the LS output pre-driver including:
a comparator having a first input, a second input, and an output, wherein the first input of the comparator is configured to receive a voltage indicative of the voltage at the drain connection;
a reference voltage selector configured to output one of a plurality of reference voltage signals to the second input of the comparator;
a multi-phase blank/filter having an input connection and an output connection, and wherein the multi-phase blank/filter is configured to blank an incoming signal received from the comparator output during a plurality of time intervals, and
a multi-phase control timer having a first timer output connection and a second timer output connection, and wherein the first timer output connection is configured to send a first signal to the reference voltage selector and the second timer output connection is configured to send a second signal to the multi-phase blank/filter; and
wherein the first signal of the multi-phase control timer instructs the reference voltage selector to select which of the plurality of reference voltage signals is provided to the second input of the comparator, and the second signal of the multi-phase control timer instructs the multi-phase blank/filter to change from one of the plurality of time intervals to another of the plurality of time intervals.

2. The low-side (LS) output pre-driver of claim 1 wherein each of the plurality of reference voltage signals is a percentage of the maximum of the battery voltage and a predetermined limit voltage.

3. The low-side (LS) output pre-driver of claim 2 wherein the predetermined limit voltage is 12 volts.

4. The low-side (LS) output pre-driver of claim 1 wherein the plurality of reference voltage signals includes a first, a second, and a third reference voltage signal.

5. The low-side (LS) output pre-driver of claim 4 wherein the reference voltage selector further includes seven resistors, a Zener diode, and a selector, and wherein the first reference voltage signal is approximately 7% of the battery voltage, the second voltage signal is approximately 50% of the battery voltage, and the third reference voltage is approximately 92% of the battery voltage.

6. The low-side (LS) output pre-driver of claim 1 wherein the plurality of reference voltage signals are obtained by a plurality of voltage divider circuits fed from a common voltage source.

7. The low-side (LS) output pre-driver of claim 1 wherein the plurality of time intervals includes a first time interval, a second time interval, and a third time interval.

8. The low-side (LS) output pre-driver of claim 7 wherein the first time interval is about 12 μsec, the second time interval is about 12 μsec, and the third time interval is about 10 μsec.

9. A low-side (LS) output pre-driver having a short-circuit-to-battery fault detection scheme for a MOSFET switch having a drain connection to a load connected to a battery voltage and a source connection tied to ground, the LS output pre-driver including:
a comparator having a first input, a second input, and an output, wherein the first input of the comparator is configured to receive a voltage indicative of the voltage at the drain connection;
a reference voltage selector configured to output one of a first reference voltage signal, a second reference voltage signal, and a third reference voltage signal, to the second input of the comparator;
a multi-phase blank/filter having an input connection and an output connection, and wherein the multi-phase blank/filter is configured to blank an incoming signal received from the comparator output during a plurality of time intervals; and
a multi-phase control timer having a first timer output connection and a second timer output connection, and wherein the first timer output connection is configured to send a first signal to the reference voltage selector and the second timer output connection is configured to send a second signal to the multi-phase blank/filter; and
wherein the first signal of the multi-phase control timer instructs the reference voltage selector to select which of the first reference voltage signal, the second reference voltage signal, and the third reference voltage signal is provided to the second input of the comparator, and the second signal of the multi-phase control timer instructs the multi-phase blank/filter to change from one of the plurality of time intervals to another of the plurality of time intervals.

10. The low-side (LS) output pre-driver of claim 9 wherein each of the reference voltage signals is a percentage of the maximum of the battery voltage and a predetermined limit voltage.

11. The low-side (LS) output pre-driver of claim 10 wherein the predetermined limit voltage is 12 volts.

12. The low-side (LS) output pre-driver of claim 9 wherein the plurality of time intervals includes a first interval, a second interval, and a third time interval.

13. The low-side (LS) output pre-driver of claim 12 wherein the first time interval is about 12 μsec, the second time interval is about 12 μsec, and the third time interval is about 10 μsec.

14. The low-side (LS) output pre-driver of claim 9 wherein the reference voltage selector further includes seven resistors, a Zener diode, and a selector, and wherein the first reference voltage signal is approximately 7% of the battery voltage, the second voltage signal is approximately 50% of the battery voltage, and the third reference voltage is approximately 92% of the battery voltage.

15. A low-side (LS) output pre-driver having a short-circuit-to-battery fault detection scheme for a MOSFET switch having a drain connection to a load connected to a battery voltage and a source connection tied to ground, the LS output pre-driver including:
a comparator having a first input, a second input, and an output, and wherein the first input of the comparator is configured to receive a voltage indicative of the voltage at the drain connection;
a reference voltage selector configured to output one of a first, a second, and a third reference voltage signal to the second input of the comparator;
a multi-phase blank/filter having an input and an output, and wherein the multi-phase blank/filter is configured to blank an incoming signal during a first interval, a second interval, and a third time interval, and
a multi-phase control timer having a first output and a second output, and wherein the first output is configured to send a first signal to the reference voltage selector and the second output is configured to send a second signal to the multi-phase blank/filter; and
wherein the first signal of the multi-phase control timer instructs the reference voltage selector to change the from one of the plurality of reference voltage signals to another of the plurality of reference voltage signals, and the second signal of the multi-phase control timer instructs the multi-phase blank/filter to change from one of a plurality of time intervals to another of the plurality of time intervals.

16. The low-side (LS) output pre-driver of claim 15 wherein each of the plurality of reference voltage signals are a percentage of the maximum of the battery voltage and a predetermined limit voltage.

17. The low-side (LS) output pre-driver of claim 16 wherein the predetermined limit voltage is 12 volts.

18. The low-sid

Assignees

• Continental automotive systems inc

Inventors

• Baik Chung Heum
• Gonzalez-Amaya Jorge

Classifications

• H03K17/0822

  in field-effect transistor switches · CPC title

• H02H3/093

  with timing means {(in general H02H3/027; thermal delay H02H3/085; timing means for undervoltage protection H02H3/247)} · CPC title

• G01R31/3644

  Constructional arrangements · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H03K2217/0027

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