Battery sensing voltage controller
A battery pack includes a housing, a battery, a battery pack output voltage path that includes a charge power switch and a discharge power switch, and a battery sense output. A switch can be operably coupled between the battery and the battery sense output and configured to selectively open and close a battery sense path between the battery and the battery sense output. By one approach a first control circuit controls the open and close state of the aforementioned switch (in response, for example, to a comparison of the voltage differential across the switch to a predetermined threshold such that the switch is opened when the voltage differential across the switch becomes too positive or too negative with respect to battery voltage).
1. An apparatus for use with a battery pack having a housing, a battery, a battery pack output voltage path that includes a charge power switch and a discharge power switch, and a battery sense output, the apparatus comprising:
a battery sense path between the battery and the battery sense output;
a switch operably coupled between the battery and the battery sense output and configured to selectively open and close the battery sense path;
a first control circuit configured to generate a first control signal based on a comparison between a voltage across the switch and a predetermined threshold;
a second control circuit configured to generate a second control signal based on a battery charge event or a battery discharge event; and
an AND gate having a first input configured to receive the first control signal a second input configured to receive the second control signal and an output configured to operate the switch.
2. The apparatus of claim 1 further comprising:
a selectively switchable current source disposed in parallel with the switch.
3. The apparatus of claim 2 wherein the selectively switchable current source has an enablement state controlled by a fault recovery signal.
4. A battery pack comprising:
a housing;
a battery disposed within the housing;
a battery pack output voltage path that includes a charge power switch and a discharge power switch disposed within the housing;
a battery sense output available external to the housing;
a switch disposed within the housing and being operably coupled between the battery and the battery sense output and configured to selectively open and close a battery sense path between the battery and the battery sense output; and
a selectively switchable current source disposed within the housing and disposed in parallel with the switch.
5. The battery pack of claim 4 and further comprising:
a first control circuit disposed within the housing and configured to control the open and close state of the switch.
6. The battery pack of claim 5 wherein the first control circuit is configured to control the open and close state of the switch in response, at least in part, to a comparison of a voltage differential across the switch to a predetermined threshold.
7. The battery pack of claim 6 further comprising:
a second control circuit disposed within the housing and also configured to control the open and close state of the switch in response, at least in part, to control signals provided to the charge power switch and the discharge power switch.
8. The battery pack of claim 7 further comprising:
an AND gate disposed within the housing and having an output coupled to a control port for the switch and having inputs respectively coupled to the first and second control circuits.
9. The battery pack of claim 4 wherein the selectively switchable current source has an enablement state controlled by a fault recovery signal.
10. An apparatus for use with a battery pack having a housing, a battery, a battery pack output voltage path that includes a charge power switch and a discharge power switch, and a battery sense output, the apparatus comprising:
a battery sense path between the battery and the battery sense output;
switch means operably coupled between the battery and the battery sense output and configured to selectively open and close the battery sense path; and
a selectively switchable current source disposed in parallel with the switch means.
11. The apparatus of claim 10 and further comprising:
first control means configured to control the open and close state of the switch means such that the switch means is opened when a voltage differential across the switch means is outside of a predetermined range of battery voltage.
12. The apparatus of claim 11 further comprising:
second control means also configured to control the open and close state of the switch means in response, at least in part, to control signals provided to the charge power switch and the discharge power switch.
13. The apparatus of claim 12 further comprising:
an AND gate having an output coupled to a control port for the switch means and having inputs respectively coupled to the first and second control means.
14. The apparatus of claim 10 wherein the selectively switchable current source has an enablement state controlled by a fault recovery signal.