Battery check device for camera

• US 4,502,774 A
• Filed: 06/07/1983
• Issued: 03/05/1985
• Est. Priority Date: 06/15/1982
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suzuki, Ryoichi, Tokuda, Ryuji
• Primary Examiner(s): Perkey, William B.
• Application Number:
  US06/501,987
• Time in Patent Office: 637 Days
• Field of Search: 354/403, 354/468, 354/484, 354/268, 354/83, 354/412, 340/663
• US Class Current: 396/129
• CPC Class Codes: G03B 7/26 Power supplies; Circuitry or arrangement to switch on the power source; Circuitry to check the power source voltage

Abstract

To accurately check a battery of a camera, a battery checking operation must be performed under maximum load current, namely, the load current of a shutter release magnet or the like. The invention avoids the effect of a current through the magnet triggering a photographic operation of the camera during a battery check by having currents flow to a plurality of selected loads of the camera, such as light emitting diodes, etc., instead of through the magnet. The plurality of loads are preselected to draw the total sum of load currents nearly equal to the maximum load current. A battery check can be performed without applying a drive current to the largest load and yet the accuracy of the battery check thus obtained equals that of the accuracy obtainable with the largest load.

Claims

1. A camera comprising:

(a) a plurality of electrical loads including an electrical load for driving a photographic operation control mechanism of the camera;

(b) a voltage check circuit arranged to detect a power source voltage; and

(c) a driving circuit for supplying currents to at least two preselected electrical loads including said electrical load for driving a photographing operation control mechanism, said driving circuit being arranged for supplying a current which is smaller than a current required for driving a photographing operation control mechanism to said load for driving said mechanism; and

(d) a control circuit arranged to actuate said driving circuit when a battery check operation is to be performed by said voltage check circuit.

2. A camera comprising:

(a) a plurality of electrical loads including an electrical load required for driving a photographing operation control mechanism of the camera;

(b) a voltage check circuit arranged to detect a power source voltage;

(c) a drive circuit arranged to supply currents to at least two preselected electrical loads which are preselected out of said electrical loads in such a manner that the total sum of load currents for the preselected loads corresponds to a maximum load current of the camera; and

(d) a control circuit arranged to actuate said drive circuit when a battery check operation is to be performed by said voltage check circuit.

3. A camera comprising:

(a) a plurality of electrical loads including the largest electrical load which is arranged for driving a photographing operation control mechanism of the camera;

(b) a voltage check circuit arranged to detect a power source voltage;

(c) a drive circuit arranged to supply currents to at least two preselected electrical loads which are preselected out of said electrical loads in such a manner that the total sum of load currents for the preselected loads corresponds to a driving current required for driving said largest electrical load; and

(d) a control circuit arranged to actuate said drive circuit when a battery check operation is to be performed by said voltage check circuit.

4. A camera comprising:

(a) a magnet functionally coupled to a photographing operation control mechanism of the camera, said magnet being arranged to actuate said mechansim when a driving current is supplied thereto;

(b) an electrical load not coupled to the photographing operation control mechanism of the camera;

(c) a power supply circuit arranged to supply said magnet with a current which is smaller than said driving current required for actuating said mechanism and also to supply said electrical load with a current;

(d) a photographing operation control circuit arranged to supply said driving current to said magnet and said electrical load at predetermined timing for a photographing operation;

(e) a voltage check circuit for checking a power source voltage; and

(f) a battery check control circuit arranged to actuate said power supply circuit when a battery checking operation is to be performed with said voltage check circuit.

5. A camera according to claim 4, wherein said electrical load is light emitting means.

6. A camera according to claim 5, wherein said light emitting means is arranged to project a light onto an object to be photographed for the purpose of automatic focusing.

7. A camera comprising:

(a) a plurality of electrical loads including the largest electrical load which is arranged to drive a photographing operation control mechanism of the camera when a driving current is supplied thereto;

(b) a voltage check circuit arranged to detect a power source voltage;

(c) a drive circuit arranged to supply currents to at least two electrical loads including said largest electrical load, said current supplied to the largest electrical load by said drive circuit being arranged to be of a value smaller than said driving current required for driving said mechanism;

(d) a photographing operation control circuit which, at the time of a photographing operation, supplies a driving current at predetermined timing to each of said electrical loads to allow them to perform the photographing operation; and

(e) a battery check control circuit arranged to actuate said drive circuit when battery check is to be performed through said voltage check circuit.

8. A camera according to claim 7, wherein the total sum value of the currents supplied from said drive circuit to said loads corresponds to a maximum load current of the camera.

9. A camera comprising:

(a) a plurality of electrical loads including an electrical load required for driving a photographic operation control mechanism of the camera;

(b) a voltage check circuit arranged to detect a power source voltage;

(c) a driving circuit arranged to supply currents to at least two preselected electrical loads which are preselected out of said electrical loads such that the total sum of load currents for the preselected loads is substantially the same as a maximum load current of the camera;

(d) a control circuit for actuating said drive circuit when a battery check operation is to be performed by said voltage check circuit.