JPS5537879A - Transistor protection circuit - Google Patents

Transistor protection circuit

Info

Publication number
JPS5537879A
JPS5537879A JP11078778A JP11078778A JPS5537879A JP S5537879 A JPS5537879 A JP S5537879A JP 11078778 A JP11078778 A JP 11078778A JP 11078778 A JP11078778 A JP 11078778A JP S5537879 A JPS5537879 A JP S5537879A
Authority
JP
Japan
Prior art keywords
resistor
transistor
power supply
connection point
load side
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.)
Granted
Application number
JP11078778A
Other languages
Japanese (ja)
Other versions
JPS5857074B2 (en
Inventor
Kimito Kosaka
Junichi Yamase
Yoshihiro Arakawa
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP11078778A priority Critical patent/JPS5857074B2/en
Publication of JPS5537879A publication Critical patent/JPS5537879A/en
Publication of JPS5857074B2 publication Critical patent/JPS5857074B2/en
Expired legal-status Critical Current

Links

Landscapes

  • Protection Of Static Devices (AREA)
  • Dc-Dc Converters (AREA)
  • Power Conversion In General (AREA)

Abstract

PURPOSE: To prevent the thermal breakdown of a transistor, by bypassing the input current of a starting resistor to lengthen the inverse bias time of the transistor when a short circuit takes place on the load side of a switching regulator type power supply circuit.
CONSTITUTION: A resistor 18 is coupled between the transistor 6 and the starting resistor 4 of the ringing-choke switching regulator type power supply circuit. A resistor 19 and a diode 20 are connected in series with each other between an output capacitor 13 and the connection point A of the resistor 4 with the resistor 18. Normally, the potential on the connection point A is almost equal to an output voltage. When there is a short circuit on the load side of the power supply circuit, a current flows to the load side through the resistor 19 and the potential on the connection point A falls. At that time, the time of return of the base potential of the transistor 6 from a negative level to zero lengthens and the period of unstable operating state of the transistor shortens. As a result, the heating of the transistor is reduced and it is protected from thermal breakdown.
COPYRIGHT: (C)1980,JPO&Japio
JP11078778A 1978-09-11 1978-09-11 transistor protection circuit Expired JPS5857074B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11078778A JPS5857074B2 (en) 1978-09-11 1978-09-11 transistor protection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11078778A JPS5857074B2 (en) 1978-09-11 1978-09-11 transistor protection circuit

Publications (2)

Publication Number Publication Date
JPS5537879A true JPS5537879A (en) 1980-03-17
JPS5857074B2 JPS5857074B2 (en) 1983-12-17

Family

ID=14544611

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11078778A Expired JPS5857074B2 (en) 1978-09-11 1978-09-11 transistor protection circuit

Country Status (1)

Country Link
JP (1) JPS5857074B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4553196A (en) * 1981-06-12 1985-11-12 Hitachi, Ltd. Power source system for vehicular electronic device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4553196A (en) * 1981-06-12 1985-11-12 Hitachi, Ltd. Power source system for vehicular electronic device

Also Published As

Publication number Publication date
JPS5857074B2 (en) 1983-12-17

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