초록 ▼

Disclosed herein is a battery charger control circuit having a voltage detector to generate a signal indicative of a source voltage level to select one of a first charging mode and a second charging mode, and a charge controller coupled to the voltage detector to enable charging in accordance with o

Disclosed herein is a battery charger control circuit having a voltage detector to generate a signal indicative of a source voltage level to select one of a first charging mode and a second charging mode, and a charge controller coupled to the voltage detector to enable charging in accordance with one of the first charging mode and the second charging mode based on the signal from the voltage detector. The first and second charging modes establish charging at differing, non-zero rates. The source voltage level may be sampled at a sampling rate to minimize power consumed by monitoring the source voltage level.

대표청구항 ▼

What is claimed is: 1. A battery charger control circuit, comprising: a window comparator configured to detect a voltage level of a power source and to compare the voltage level against a predetermined range to generate a first control signal and a second control signal indicative of the voltage le

What is claimed is: 1. A battery charger control circuit, comprising: a window comparator configured to detect a voltage level of a power source and to compare the voltage level against a predetermined range to generate a first control signal and a second control signal indicative of the voltage level of the power source, the first control signal and second control signal logically combined to generate a third signal coupled to a control switch that enables charging using any one of a first charging mode or a second charging mode used in charging a battery from the power source; a charge controller coupled to the window comparator, configured to enable charging the battery in accordance with one of the first charging mode or the second charging mode based on the first control signal or the second control signal indicative of the voltage level of the power source; and, wherein the first and second charging modes establish charging from the power source to the battery at differing, non-zero rates. 2. The battery charger control circuit of claim 1, wherein the first and second control signals generated by the window comparator are configured to indicate whether the power source voltage level is below, within, or above the predetermined range which is a voltage window set by the window comparator. 3. The battery charger control circuit of claim 2, wherein the control switch is configured to determine whether the charge controller should be powered based on whether the first and second control signals indicate that the source voltage level is below the voltage window. 4. The battery charger control circuit of claim 3, further comprising an OR gate responsive to the first and second control signals to drive the control switch. 5. The battery charger control circuit of claim 1, wherein the charge controller comprises a fast-charge controller integrated circuit such that the first and second charging modes correspond with trickle and fast charging, respectively. 6. The battery charger control circuit of claim 5, wherein a signal of the voltage level of the power source is provided to a temperature threshold pin of the fast-charge controller integrated circuit to disable fast charging. 7. The battery charger control circuit of claim 1, further comprising a step-up, DC-DC controller coupled to the charge controller. 8. The battery charger control circuit of claim 7, wherein the step-up, DC-DC controller comprises a switching regulator. 9. A battery charger control circuit, comprising: a window comparator configured to detect a voltage level of a power source and to compare the voltage level against a predetermined range to generate a first control signal and a control second signal indicative of a voltage level of the power source, the first control signal and second control signal logically combined to generate a third signal coupled to a control switch that enables charging using any one of a first charging mode or a second charging mode, wherein the first charging mode and the second charging mode are configured to charge a battery from the power source; and, a charge controller coupled to the window comparator, configured to enable charging in accordance with one of the first charging mode or the second charging mode based on the first control signal or the second control signal indicative of the voltage level of the power source; wherein the first and second charging modes establish charging from the power source to the battery at differing, non-zero rates, as determined by the first control signal or the second control signal; wherein the window comparator comprises an oscillator to enable sampling of the source voltage level. 10. The battery charger control circuit of claim 1, wherein the first and second charging modes are two of a plurality of operational modes of the battery charger control circuit, the plurality of operational modes including a non-charging mode, and wherein the window comparator is connected to the source battery to monitor the source voltage level regardless of the operational mode of the battery charger control circuit. 11. A vehicle electrical system having a primary battery with a terminal voltage, the vehicle electrical system comprising: a secondary battery; and, a control circuit configured to couple the secondary battery to the primary battery to control recharging of the secondary battery via the primary battery, the control circuit comprising: a window comparator configured to detect a source voltage level of the primary battery and to compare the source voltage level against a predetermined range to generate a first control signal and a second control signal indicative of the terminal voltage of the primary battery, the first control signal and second control signal logically combined to generate a third signal coupled to a switch that enables charging using any one of a first charging mode or a second charging mode, wherein the first charging mode and the second charging mode are configured to charge the secondary battery from the primary battery; and, a charge controller configured to enable charging of the secondary battery in accordance with one of the first or second charging modes based on the first control signal or the second control signal; wherein the first and second charging modes establish charging from the primary battery to the secondary battery at differing, non-zero rates. 12. The vehicle electrical system of claim 11, wherein the first and second control signals generated by the window comparator are configured to indicate whether the source voltage level is below, within, or above a voltage window set by the window comparator. 13. The vehicle electrical system of claim 12, wherein the control switch is configured to determine whether the charge controller should be powered based on whether the first and second control signals indicate that the source voltage level is below the voltage window. 14. The vehicle electrical system of claim 13, wherein the control circuit further comprises an OR gate responsive to the first and second control signals to drive the control switch. 15. The vehicle electrical system of claim 11, wherein the charge controller comprises a fast-charge controller integrated circuit such that the first and second charging modes correspond with trickle and fast charging, respectively. 16. The vehicle electrical system of claim 15, wherein a signal of the voltage level of the source is provided to a temperature threshold pin of the fast-charge controller integrated circuit to disable fast charging. 17. The vehicle electrical system of claim 11, wherein the window comparator comprises an oscillator to enable sampling of the terminal voltage. 18. The vehicle electrical system of claim 11, wherein the window comparator uses the terminal voltage as a power supply. 19. The vehicle electrical system of claim 11, wherein the first and second charging modes are two of a plurality of operational modes of the control circuit, the plurality of operational modes including a non-charging mode, and wherein the window comparator is connected to the primary battery to monitor the terminal voltage regardless of the operational mode of the control circuit. 20. A battery charger control circuit, comprising: a window comparator to generate first and second signals collectively indicative of whether a source voltage level is below, within or above a voltage window to select one of a plurality of operational modes, wherein the window comparator has an oscillator to establish a sampling rate such that the source voltage level is sampled at the sampling rate to minimize power consumed by monitoring the source voltage level; mode-select logic circuitry that couples the first and second control signals to produce a third signal that is coupled to a control switch that drives charging using any one of the operational modes; and, a charge controller coupled to the window comparator to enable charging from a source voltage to a battery in accordance with the selected operational mode. 21. The battery charger control circuit of claim 20, wherein the plurality of operational modes includes first and second charging modes that establish charging at differing, non-zero rates. 22. The battery charger control circuit of claim 21, wherein the plurality of operational modes includes a non-charging mode, and the window comparator is in communication with the source voltage level such that the window comparator monitors the source voltage level during the non-charging mode. 23. The battery charger control circuit of claim 20, the control switch controlled by at least one of the first and second signals to determine whether the charge controller is powered. 24. The battery charger control circuit of claim 23, further comprising an OR gate coupling the window comparator and the control switch such that either one of the first and second signals may activate the control switch to allow the charge controller to be powered. 25. A vehicle electrical system having a primary battery with a terminal voltage, the vehicle electrical system comprising: a secondary battery; and, a control circuit configured to couple the secondary battery to the primary battery to control recharging of the secondary battery via the primary battery, the control circuit comprising: a window comparator configured to detect the terminal voltage of the primary battery and to compare the terminal voltage level against a predetermined range to generate a first control signal and a second control signal indicative of the terminal voltage of the primary battery, the first control signal and second control signal logically combined to generate a third signal coupled to a switch that drives charging using any one of a first charging mode or a second charging mode; and, a charge controller configured to enable charging of the secondary battery in accordance with one of the first or second charging modes based on the first control signal or the second control signal indicative of the terminal voltage of the primary battery; wherein the first and second charging modes establish charging from the primary battery to the secondary battery at differing, non-zero rates; wherein the charge controller is configured to charge the secondary battery so the secondary battery powers an accessory device when the accessory device is not in an operation mode. 26. The battery charger control circuit of claim 1, wherein the charge controller is configured to maintain a continuous charging, without stopping charging, of the battery from the power source while switching between the first charging mode and the second charging mode. 27. The battery charger control circuit of claim 9, wherein the charge controller is configured to maintain a continuous charging, without stopping charging, of the battery from the power source while switching between the first charging mode and the second charging mode. 28. The vehicle electrical system of claim 11, wherein the charge controller is configured to maintain a continuous charging, without stopping charging, of the secondary battery from the primary battery while switching between the first charging mode and the second charging mode. 29. The battery charger control circuit of claim 21, wherein the charge controller is configured to maintain a continuous charging, without stopping charging, of the secondary battery from the primary battery while switching between the first charging mode and the second charging mode. 30. The vehicle electrical system of claim 25, wherein the charge controller is configured to maintain a continuous charging, without stopping charging, of the secondary battery from the primary battery while switching between the first charging mode and the second charging mode. 31. The battery charger control circuit of claim 2, wherein the window comparator includes at a first comparator and a second comparator that are configured in parallel with respect to a signal indicative of the voltage level of the power source. 32. The battery charger control circuit of claim 10, wherein the window comparator includes at a first comparator and a second comparator that are configured in parallel with respect to a signal indicative of the voltage level of the power source. 33. The vehicle electrical system of claim 12, wherein the window comparator includes at a first comparator and a second comparator that are configured in parallel with respect to a signal indicative of the terminal voltage level of the primary battery. 34. The battery charger control circuit of claim 21, wherein the window comparator includes at a first comparator and a second comparator that are configured in parallel with respect to a first and second signals indicative of the source voltage level of a primary battery. 35. The vehicle electrical system of claim 25, further including a window comparator, wherein the window comparator includes at a first comparator and a second comparator that are configured in parallel with respect to a signal indicative of the terminal voltage level of a primary battery.