JPS5491276A - Driving circuit of illumination lamp for wristwatch - Google Patents

Driving circuit of illumination lamp for wristwatch

Info

Publication number
JPS5491276A
JPS5491276A JP16084277A JP16084277A JPS5491276A JP S5491276 A JPS5491276 A JP S5491276A JP 16084277 A JP16084277 A JP 16084277A JP 16084277 A JP16084277 A JP 16084277A JP S5491276 A JPS5491276 A JP S5491276A
Authority
JP
Japan
Prior art keywords
lamp
switch
mos
pull
resistance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP16084277A
Other languages
Japanese (ja)
Inventor
Takehiro Ishikawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Instruments Inc
Original Assignee
Seiko Instruments Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Seiko Instruments Inc filed Critical Seiko Instruments Inc
Priority to JP16084277A priority Critical patent/JPS5491276A/en
Publication of JPS5491276A publication Critical patent/JPS5491276A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04G—ELECTRONIC TIME-PIECES
    • G04G9/00—Visual time or date indication means
    • G04G9/0023—Visual time or date indication means by light valves in general
    • G04G9/0029—Details
    • G04G9/0047—Details electrical, e.g. selection or application of the operating voltage
    • G04G9/0052—Details electrical, e.g. selection or application of the operating voltage using means to adjust the display in accordance with the ambient light, e.g. switching or controlling a supplementary light source

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Liquid Crystal (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Electric Clocks (AREA)

Abstract

PURPOSE:To extend the life of the filament of a lmap, by changing the impedance from lit time to unlit time. CONSTITUTION:Between a switch 1 and a lamp 7 are provided pull-up resistance 2, pull-down resistance 3, P channel MOS FETs 4, 5, and N channel MOD FET 6. When the switch 1 is OFF, the impedances of MOS FETs 4, 5 are high and MOS FET 6 remains OFF, so that no current flows into the lamp 7. When the switch 1 is ON, the potential of V1 is determined by the resistance division of ON resisrance of MOS FET 4 and pull-down resistance 3, while MOS FET 6 is slightly ON to suppress the surge current. As the switch 1 continues to be ON, MOS FET 5 is gradually turned ON, and the impedance drops, so that the current flow into the lamp 7 increases gradually. Therefore, the surge current at the time of lamp lighting is suppressed, so that the life of the lamp 7 may be longer.
JP16084277A 1977-12-27 1977-12-27 Driving circuit of illumination lamp for wristwatch Pending JPS5491276A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16084277A JPS5491276A (en) 1977-12-27 1977-12-27 Driving circuit of illumination lamp for wristwatch

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16084277A JPS5491276A (en) 1977-12-27 1977-12-27 Driving circuit of illumination lamp for wristwatch

Publications (1)

Publication Number Publication Date
JPS5491276A true JPS5491276A (en) 1979-07-19

Family

ID=15723577

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16084277A Pending JPS5491276A (en) 1977-12-27 1977-12-27 Driving circuit of illumination lamp for wristwatch

Country Status (1)

Country Link
JP (1) JPS5491276A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2522142A1 (en) * 1982-02-19 1983-08-26 Terumo Corp ELECTRONIC CLINICAL THERMOMETER
JP2008264435A (en) * 2007-04-25 2008-11-06 Daiman:Kk Game machine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2522142A1 (en) * 1982-02-19 1983-08-26 Terumo Corp ELECTRONIC CLINICAL THERMOMETER
JP2008264435A (en) * 2007-04-25 2008-11-06 Daiman:Kk Game machine

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