Voltage regulator circuit

• US 4,667,145 A
• Filed: 05/01/1986
• Issued: 05/19/1987
• Est. Priority Date: 10/08/1985
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Moreau, Alain
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Jones, Judson H.
• Application Number:
  US06/858,157
• Time in Patent Office: 383 Days
• Field of Search: 323/231, 323/275, 323/280, 323/281, 323/314
• US Class Current: 323/275
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit

Abstract

A highly stable voltage regulator circuit based on a low-voltage reference and supplying a voltage which is substantially higher than the reference voltage. The circuit is to be constructed as an integrated circuit comprising transistors of one conductivity type and without a zener diode.

The reference voltage is supplied by a "band-gap reference" circuit (1). A differential circuit (T16, T17) controls the output voltage, which is applied to the base of a transistor (T16) via a resistor (R16) in which the current is maintained constant by means of an associated differential circuit (T11, T12) which comprises a resistor (R11) connected between its emitters. The bases of the transistors T11, T12 are each connected to one end of a resistor (R20) arranged in a bridge connected between the reference terminal and ground.

Claims

1. A voltage regulator circuit composed of transistors of a single conductivity type and resistors, comprising:

a reference-voltage source, whose voltage is smaller than the voltage to be supplied, connected to a common terminal,

a load element connected between an input terminal and an output terminal and which is controlled by

a first comparator circuit for comparing a reference voltage and a voltage which is a function of the voltage at the output terminal,

a resistor voltage divider conncected between the reference-voltage source and the common terminal, and

a differential circuit comprising a first transistor having its base connected to one end of one of the resistors of said voltage divider and having its emitter connected to a first current source , said differential circuit comprising a second transistor having its base connected to the other end of said one resistor of said voltage divider and having its emitter connected to the emitter of said first transistor via a second resistor, and means connecting the collector of the second transistor to the output terminal via a third resistor to supply said voltage which is a function of the voltage at the output terminal.

2. A voltage regulator circuit as claimed in characterized in that it comprises a second comparator circuit for comparing a fraction of the input voltage with the reference voltage, and means connecting the second comparator circuit to the load element to supply to said element a current which is a function of the voltage at the input terminal.

3. A voltage regulator circuit as claimed in claim 2, characterized in that the collector of the first transistor of said differential circuit is connected to the second comparator circuit for supplying a constant current to the second comparator circuit.