Electronic circuit

• US 20060256592A1
• Filed: 04/26/2006
• Published: 11/16/2006
• Est. Priority Date: 04/28/2005
• Status: Abandoned Application

• Current Assignee: MyShape, Inc., Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: MyShape, Inc.
• Inventors: Utsunomiya, Fumiyasu, Yoshida, Yoshifumi
• Application Number:
  US11/412,312
• Publication Number:
  US 20060256592A1
• Time in Patent Office: Days
• US Class Current: 363/59
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/073 Charge pumps of the Schenkel-type

Abstract

Provided is an electronic device having a booster circuit, in which a booster circuit and other circuits are prevented from being damaged even when a voltage that is equal to or higher than a standard voltage is inputted. The booster circuit for boosting an input voltage and outputting the boosted voltage has an input voltage limiter circuit for regulating an upper limit of an output voltage, and a booster circuit for boosting the input voltage at a fixed magnification by using a capacitor.

Claims

1. An electronic device, comprising:

a voltage limiter circuit that is connected to an input terminal and regulates an upper limit of an input voltage which is inputted to the input terminal; and

a booster circuit that is connected to the voltage limiter circuit and boosts the input voltage to a fixed magnification to output the boosted voltage to an output terminal.

2. An electronic circuit according to claim 1, wherein the booster circuit comprises:

a clock generator circuit for generating a clock signal;

a rectifier element; and

a capacitor.

3. An electronic circuit according to claim 2, wherein the rectifier element comprises a MOSFET connected with a diode.

4. An electronic circuit according to claim 1, wherein:

the booster circuit comprises;

a booster unit circuit including a diode or an anode of a MOSFET connected with a diode as an input terminal, and a capacitor having one electrode connected to the diode or a cathode of the MOSFET connected with the diode; and

a clock generator circuit connected to another electrode of the capacitor, and

one of more of the boost unit circuits are provided to be connected in cascade.

5. An electronic circuit according to claim 1, wherein:

the booster circuit has a plurality of booster unit circuits;

the plurality of booster unit circuit has a configuration in which;

a drain of a first MOSFET is connected to a drain of a second MOSFET to form an input terminal;

a source of the first MOSFET is connected to a drain of a third MOSFET and to a first electrode of a capacitor;

a source of the second MOSFET is connected to a second electrode of the capacitor and to a drain of a fourth MOSFET;

a source of the fourth MOSFET is used as an output terminal;

a source of the third MOSFET is grounded;

the gates of the first and third MOSFETs are connected to the clock output terminal of a clock generator circuit;

a gate of the second MOSFET and an input terminal of a level shift circuit are connected to an inverting clock output terminal of a clock generator circuit; and

an output terminal of the level shifter circuit is connected to a gate terminal of the fourth MOSFET; and

the plurality of booster unit circuits are connected in cascade.

6. An electronic circuit according to claim 1, wherein:

the voltage limiter circuit comprises;

a constant voltage generator circuit for inputting the input voltage and outputting a constant voltage; and

a depletion type MOSFET having a gate voltage controlled by the constant voltage outputted from the constant voltage generator circuit.

7. An electronic circuit according to claim 6, wherein:

the constant voltage generator circuit comprises;

a constant current source; and

a resistant element,

the constant current source and the resistant element being connected in series to each other between the input terminal and a ground terminal; and

the input terminal is formed of a connection point at which the constant current source and the resistant element are connected to each other.

8. An electronic circuit according to claim 7, wherein the constant current source comprises a depletion type MOSFET having a gate and a source connected to each other.

9. An electronic circuit according to claim 7, wherein the resistant element comprises a MOSFET connected with a diode.