BATTERY CHARGER

• US 20150256015A1
• Filed: 12/18/2014
• Published: 09/10/2015
• Est. Priority Date: 03/05/2014
• Status: Active Grant

• Current Assignee: Jonathan J. Hull, Kenneth Gudan, Matthew S. Reynolds
• Original Assignee: Jonathan J. Hull, Kenneth Gudan, Matthew S. Reynolds
• Inventors: Hull, Jonathan J., Reynolds, Matthew S., Gudan, Kenneth
• Granted Patent: US 10,468,917 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01H 7/00 Devices for introducing a predetermined time delay between the initiation of the switching operation and the opening or closing of the contacts time or time-programme switches H01H43/00
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

A battery charger for charging a battery is disclosed. In one embodiment, the battery charger comprises an input for receiving a first voltage and for coupling to a positive terminal of the battery; a first transistor having a first gate, a first drain and a first source, wherein the first gate is for coupling to a charging signal for the battery and the first drain is coupled to the battery negative terminal and, the first transistor to cause energy to be transferred from the input into the battery when turned on; and a group of transistors coupled to the first transistor and the input to control when the first transistor is turned on, wherein the group of transistors comprises a second transistor having a second gate coupled to the input and coupled to a third transistor to turn off the third transistor after a delay occurs after the voltage on the input reaches a predetermined level, and further herein the third transistor causes the first transistor to turn on when the third transistor is turned off.

Claims

1. A battery charger for charging a battery, the battery charger comprising:

an input for receiving a first voltage and for coupling to a positive terminal of the battery;

a first transistor having a first gate, a first drain and a first source, the first gate for coupling to a charging signal for the battery, the first drain coupled to a negative terminal of the battery and, connects the battery negative terminal to ground when the transistor is on, thereby causing energy to be transferred from the input into the battery; and

a group of transistors coupled to the first transistor and the input to control when the first transistor is turned on, wherein the group of transistors comprises a second transistor having a second gate coupled to the input and coupled to a third transistor to turn off the third transistor after a delay occurs after the voltage on the input reaches a predetermined level, the third transistor causing the first transistor to turn on when the third transistor is turned off.

2. The battery charger defined in claim 1 further comprising a plurality of diodes connected in a cascaded arrangement between the input and the gate of the second transistor to control the second transistor based by forcing diode voltage drops onto the gate of the second transistor.

3. The battery charger defined in claim 1 wherein the third transistor is an inversion transistor.

4. The battery charger defined in claim 1 further comprising a resistor-capacitor (RC) circuit coupled to the third gate to cause the delay.

5. The battery charger defined in claim 1 wherein the first transistor comprise a n-channel MOSFET.

6. The battery charger defined in claim 1 wherein the group of transistors comprise n-channel MOSFETs.

7. The battery charger defined in claim 1 further comprising a diode for coupling in series between the input and the positive terminal of the battery to prevent reverse current from the battery to the input.

8. The battery charger defined in claim 1 further comprising a diode coupled between ground and the second gate for stability and over-voltage protection.

9. A device comprising:

an antenna;

a load; and

an energy harvester coupled to the antenna and the load, wherein the energy harvester comprises

a battery to store energy, and

a battery charger having

an input for receiving a first voltage and for coupling to a positive terminal of the battery,

a first transistor having a first gate, a first drain and a first source, the first gate for coupling to a charging signal for the battery, the first drain coupled to a negative terminal of the battery and, connects the battery negative terminal to ground when the transistor is on, thereby causing energy to be transferred from the input into the battery; and

a group of transistors coupled to the first transistor and the input to control when the first transistor is turned on, wherein the group of transistors comprises a second transistor having a second gate coupled to the input and coupled to a third transistor to turn off the third transistor after a delay occurs after the voltage on the input reaches a predetermined level, the third transistor causing the first transistor to turn on when the third transistor is turned off; and

an energy storage reservoir coupled to the output of the DC/DC converter to store energy at the second voltage.

10. The device defined in claim 9 wherein the rechargeable battery is a Nickel Metal Hydride (NiMH) battery.

11. The device defined in claim 9 further comprising a plurality of diodes connected in a cascaded arrangement between the input and the gate of the second transistor to control the second transistor based by forcing diode voltage drops onto the gate of the second transistor.

12. The device defined in claim 9 further comprising a resistor-capacitor (RC) circuit coupled to the third gate to cause the delay.

13. The device defined in claim 9 wherein the first transistor comprise a n-channel MOSFET.

14. The device defined in claim 9 wherein the group of transistors comprise n-channel MOSFETs.

15. The device defined in claim 9 further comprising a diode for coupling in series between the input and the positive terminal of the battery to prevent reverse current from the battery to the input.

16. The device defined in claim 9 further comprising a diode coupled between ground and the second gate.

17. A battery charger for charging a battery, the battery charger comprising:

an input for receiving a first voltage and for coupling to a positive terminal of the battery;

first and second transistors for transferring the first voltage from the input into the battery when turned on, each of the first and second transistors having a gate; and

a group of transistors coupled to the first and second transistors to control when the first and second transistors are turned on, wherein the group of transistors generate first and second control signals to gates of the first and second transistors, respectively, to turn on the first and second transistors in response to the first voltage being at least at a predetermined level, the second control signal being generated after the first control signals, thereby causing a delay between the first and second control signals, thereby causing the second transistor to turn on after the first transistor is turned on.

18. The battery charger defined in claim 17 wherein the group of transistors comprises a first pair of MOSFET transistors to generate the first and second control signals in response to the first voltage being received on a gate of a first of the transistors in the pair of n-channel MOSFET transistors, the second control signal being generated by a second transistor in the pair of n-channel MOSFET transistors.

19. The battery charger defined in claim 18 wherein the first pair of MOSFET transistors comprise n-channel MOSFET transistors.

20. The battery charger defined in claim 18 wherein the group of transistors includes a second pair of transistors, a first transistor of the second pair of transistors having a gate coupled to the drain of the first transistor of the first pair of transistors and a second transistor of the second pair of transistors having a gate coupled to the drain of the second transistor of the first pair of transistors, and further wherein gates of the first and second transistors in the second pair of transistors are coupled to the first and second control signals and drains of the second pair of transistors are coupled to the positive terminal of the battery.