Circuit and method for adjusting safety time-out with charge current
First Claim
1. A circuit for charging a battery, comprising:
- a power pass circuit that is arranged to receive a power source voltage and to provide a regulated charge current in response to the power source voltage and a control voltage;
a sense circuit that is arranged to receive the charge current and to provide a sense signal in response to the charge current;
a charge current control circuit that is arranged to receive the sense signal and to provide the control voltage based on the sense signal;
a timer control circuit that is arranged to provide a timer control signal with a frequency that is based, in part, on the sense signal; and
a safety timer circuit that is arranged to deactivate and reactivate the charge current control circuit based on the timer control signal and to detect an amount of charging time based on the frequency of the timer control signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and circuit for adjusting a safety time-out in charging devices based on a charge current. According to one embodiment, a signal that is based on the charge current is employed to control an output of an oscillator, which controls an operation of a safety timer circuit. The safety timer circuit activates or deactivates a voltage-current (V-I) control loop of the charging device providing the safety time-out based on the charge current. In another embodiment, where a digital current-set circuit may be employed to determine a value of the charge current, a Digital-to-Analog Converter (DAC) may provide the charge current limit to the V-I control loop, and another output of the digital current-set circuit may control the safety timer. In a further embodiment, a signal based on the charge current may be digitized and employed to control the safety timer comprising a time-out counter.
12 Citations
11 Claims
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1. A circuit for charging a battery, comprising:
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a power pass circuit that is arranged to receive a power source voltage and to provide a regulated charge current in response to the power source voltage and a control voltage; a sense circuit that is arranged to receive the charge current and to provide a sense signal in response to the charge current; a charge current control circuit that is arranged to receive the sense signal and to provide the control voltage based on the sense signal; a timer control circuit that is arranged to provide a timer control signal with a frequency that is based, in part, on the sense signal; and a safety timer circuit that is arranged to deactivate and reactivate the charge current control circuit based on the timer control signal and to detect an amount of charging time based on the frequency of the timer control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification