Charger using one or more solar batteries

• US 4,311,953 A
• Filed: 10/22/1979
• Issued: 01/19/1982
• Est. Priority Date: 08/17/1976
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fukuda, Hiroaki, Sasaki, Takehiko, Mori, Hiroshi
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US06/086,793
• Time in Patent Office: 820 Days
• Field of Search: 320/2-5, 320/15, 320/39, 320/61, 320/40, 320/22-24, 320/57, 323/15, 368/204, 368/205
• US Class Current: 320/101
• CPC Class Codes: G04G 19/00 Electric power supply circuits specially adapted for use in electronic time-pieces
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y10S 136/293 Circuits
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

A charger, which is useful to power a variety of compact type electronic appliances such as an electronic wristwatch, includes one or more solar batteries as a primary battery, and a sealed type silver oxide battery as a secondary battery. Both the amount of charging current amplitude and of charging voltage are limited to protect the sealed silver oxide battery from its own expanse phenomenon.

Claims

1. A charging circuit including a solar battery and a silver oxide secondary battery, said charging circuit delivering a charging voltage and a charging current to said silver oxide secondary battery, comprising:

voltage limiting means shunting said solar battery for limiting said charging voltage across said secondary battery to a predetermined value, said voltage limiting means including a PN junction diode means in series with a light-emitting diode means; and

current limiting means in series with the combination of said solar battery and said voltage limiting means shunting said solar battery for limiting said charging current through said secondary battery.

2. The charging circuit as recited in claim 1, wherein the charging voltage limiting means and the charging current limiting means are enabled only when said solar battery is working.

3. The charging circuit as recited in claim 1, wherein said secondary battery comprises at least one sealed type silver oxide battery.

4. The charging circuit as recited in claim 1, wherein said secondary battery comprises one or more sealed type mercury batteries.

11. A charging circuit in accordance with claim 1 wherein said voltage limiting means further comprises variable adjustment means for variably adjusting the magnitude of said predetermined value.

5. A charging circuit delivering a charging voltage and a charging current to a secondary battery means comprising:

at least one solar battery;

a current limiting means in series with said solar batteries for limiting said current to said secondary battery means;

a reverse current preventing diode connected in series with said current limiting means;

at least one sealed type silver oxide battery connected in parallel with said at least one solar battery via said series circuit of said reverse current preventing diode and said current limiting means, said at least one silver oxide battery serving as said secondary battery means for said at least one solar battery; and

a voltage switching circuit means responsive to the voltage delivered from said solar battery for limiting the charging voltage from said solar battery to a predetermined value when charging said at least one silver oxide battery, said voltage switching circuit means including a PN junction diode means in series with a light emitting diode means.

6. A charging circuit delivering a charging current and a charging voltage to a secondary battery means, comprising:

at least one solar battery having an output voltage;

at least one sealed type silver oxide secondary battery means being charged with said output voltage of said at least one solar battery;

a reverse-current preventing diode means connected between said at least one solar battery and said secondary battery means;

current limiting means in series with said at least one solar battery for limiting the charging current to said secondary battery means; and

a voltage switching circuit means for limiting said charging voltage across said secondary batteries to a predetermined value, said predetermined value of said charging voltage being variably adjustable by said voltage switching circuit means, said voltage switching circuit means comprising a voltage sensing transistor means, a characteristic improving transistor means responsive to said voltage sensing transistor means and switching transistor means responsive to said characteristic improving transistor means, said switching transistor means being connected in a Darlington connection thereby increasing the current gain associated with said charging circuit.

7. The charging circuit as recited in claim 6, wherein said voltage switching circuit is implemented by utilizing integrated circuit technology.

9. The charging circuit as recited in claim 6, wherein said reverse-current preventing diode comprises a Schottkey barrier diode means.

8. A method of charging at least one sealed type silver oxide secondary battery whose charging current and charging voltage is supplied from at least one solar battery, said at least one sealed type silver oxide secondary battery having a tendency to swell out after the full charged voltage and current condition is achieved, said method comprising the steps of:

selecting a desired maximum magnitude of said charging voltage desired to be delivered from said at least one solar battery;

limiting the charging voltage across said at least one silver oxide secondary battery to said desired maximum magnitude by utilizing a PN junction diode means in series with a light-emitting diode means; and

limiting the charging current to said at least one silver oxide secondary battery, simultaneously with said limitation of said charging voltage across said at least one secondary battery.

10. A charging circuit for delivering a charging current and a charging voltage to a secondary battery means, comprising:

at least one solar battery having an output voltage;

switching means shunting said at least one solar battery for switching to an ON condition and an OFF condition in response to said output voltage delivered by said at least one solar battery, said switching means switching to said ON condition when said output voltage of said at least one solar battery exceeds a predetermined value, said switching means switching to said OFF condition when said output voltage from said at least one solar battery has a value below said predetermined value, said switching means providing an approximate short circuit across said at least one solar battery when said switching means is switched to said ON condition thereby placing a limit on said predetermined value of said output voltage from said solar battery in charging said secondary battery, said switching means including a PN junction diode means in series with a light-emitting diode means;

variable adjustment means connected across said at least one solar battery and to an input terminal of said switching means for variably adjusting the magnitude of said predetermined value of said output voltage from said at least one solar battery required to switch said switching means to said ON condition;

current limiting means in series with the parallel combination of said at least one solar battery, and said switching means, for limiting the flow of said charging current from said solar battery in charging said secondary battery means,

said secondary battery being charged by said charging current passing through said current limiting means, said secondary battery comprising a silver oxide battery.