BATTERY CHARGER

• US 20150380966A1
• Filed: 05/29/2015
• Published: 12/31/2015
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Alessandro, Agatino Antonino, Arcidiacono, Liliana, Santagati, Carmelo Alberto, Pirozzi, Francesco
• Granted Patent: US 9,735,599 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery charger includes an input supply terminal configured to receive a supply signal and a battery terminal configured to be connected to a battery. A supply switching circuit is arranged between the battery terminal and the input supply terminal. A control device generates a control signal to control operation of the supply switching circuit. A fuel gauge device provide a digital estimation of a voltage signal across the battery. A correction device modifies the control signal in response to the digital estimation of the voltage signal across the battery if that digital estimation is outside of a value range between two thresholds.

Claims

1. A battery charger, comprising:

an input supply terminal configured to receive a supply signal,

a battery terminal configured to be connected to a battery,

a supply switching circuit arranged in an electrical path between the battery terminal and the input supply terminal,

a control device configured to generate a control signal to control operation of the supply switching circuit,

a fuel gauge device configured to provide a digital estimation of a voltage signal across the battery,

a correction device configured to modify said control signal generated by the control device if said digital estimation of the voltage signal across the battery is out of a value range between a first threshold and a second threshold, wherein the first threshold is lower than the second threshold.

2. The battery charger according to claim 1, wherein the control device is configured to generate the control signal in response to a difference between the voltage signal across the battery and a reference signal, wherein the correction device is configured to modify said reference signal if said digital estimation of the voltage signal across the battery is out of said value range.

3. The battery charger according to claim 2, wherein said correction device is configured to increase the reference signal if said digital estimation of the voltage signal across the battery is lower than the first threshold and configured to decrease the reference signal if said digital estimation of the voltage signal across the battery is higher than the second threshold.

4. The battery charger according to claim 3, wherein said correction device comprises:

a first digital comparator configured to compare said digital estimation of the voltage signal across the battery with the second threshold, and

a second digital comparator configured to compare said digital estimation of the voltage signal across the battery with the first threshold,

an up/down counter configured to increase by one step if the output signal of the second digital comparator is in an active logic state and to decrease by one step if the output signal of the first digital comparator is in the active logic state.

5. The battery charger according to claim 1, wherein the battery charger comprises an enabling circuit of the correction device configured to enable the correction device only when the charging phase of the battery is operating at a constant voltage phase.

6. The battery charger according to claim 5, wherein the enabling circuit of the correction device comprises a comparison circuit configured to compare the voltage across the battery (Vbat) with a programmed floating voltage level of the battery,

said comparison circuit configured to emit a signal at an active logic state when the voltage across the battery is close to the programmed floating voltage level of the battery.

7. A method of operating a battery charger, wherein the battery charger includes an input supply terminal configured to receive a supply signal, a battery terminal configured to be connected to a battery, and a supply switching circuit arranged in an electrical path between the battery terminal and the input supply terminal, the method comprising:

controlling said supply switching circuit,

generating a digital estimation of a voltage signal across the battery,

modifying the controlling of the supply switching circuit if said digital estimation of the voltage signal across the battery which is outside of a value range between a first threshold and a second threshold, wherein the first threshold is lower than the second threshold.

8. The method according to claim 7, wherein the controlling step is effectuated in response to a difference between the voltage signal across the battery and a reference signal, wherein the modifying step comprises modifying said reference signal if said digital estimation of the voltage signal across the battery is outside of said value range.

9. The method according to claim 8, wherein said modifying step comprises:

increasing the reference signal if said digital estimation of the voltage signal across the battery is lower than the first threshold, and

decreasing the reference signal if said digital estimation of the voltage signal across the battery is higher than the second threshold.

10. The method according to claim 7, further comprising enabling the modifying step only when the charging phase of the battery is operating in a constant voltage phase.

11. An integrated circuit, comprising:

circuitry formed in one chip of semiconductor material including;

an input supply terminal configured to receive a supply signal,

a battery terminal configured to be connected to a battery,

a supply switching circuit arranged in an electrical path between the battery terminal and the input supply terminal,

a control device configured to generate a control signal to control operation of the supply switching circuit,

a fuel gauge device configured to provide a digital estimation of a voltage signal across the battery, and

a correction device configured to modify said control signal generated by the control device if said digital estimation of the voltage signal across the battery is out of a value range between a first threshold and a second threshold, wherein the first threshold is lower than the second threshold.