Voltage regulator for generating a constant reference voltage which does not change over time or with change in temperature

• US 5,184,061 A
• Filed: 05/30/1991
• Issued: 02/02/1993
• Est. Priority Date: 03/27/1991
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Bang-Wan, Bae, Yl-Sung
• Primary Examiner(s): BEHA JR, WILLIAM
• Application Number:
  US07/708,285
• Time in Patent Office: 614 Days
• Field of Search: 307/264, 307/320, 307/490, 323/234, 323/265, 323/280, 323/313, 323/907, 357/23.5, 341/122
• US Class Current: 323/265
• CPC Class Codes: G05F 1/461 using an operational amplifier as final control device
• CPC Class Codes: G05F 3/24 wherein the transistors are of the field-effect type only G05F3/205, G05F3/26, G05F3/30 take precedence
• CPC Class Codes: G05F 3/30 Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities G05F3/26 takes precedence
• CPC Class Codes: H01L 27/0214 for internal polarisation, e.g. I2L
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 323/907 Temperature compensation of semiconductor

Abstract

An improved voltage reference circuit is shown for use in analog integrated circuits including A/D and D/A converters. The voltage reference circuit comprises an operational amplifier having an non-inverting terminal connected to a capacitor. The inverting terminal of the op amp is connected to the op amp output terminal. The output terminal provides a constant reference voltage which is a function of the voltage charged in the capacitor. The capacitor includes a floating gate, an isolating layer, and a controlling gate which is used to charge (program) the capacitor to a fixed voltage. The capacitor structure is such that its charge is maintained constant over time independent of any temperature change. As a result, the voltage reference circuit prevents fluctuations in the output reference voltage throughout its operating period.

Claims

1. A voltage regulator circuit comprising:

an operational amplifier including an inverting terminal, a non-inverting terminal, and an output terminal electrically connected to said inverting terminal; and

a capacitor including a floating gate, a controlling gate, and an isolating layer, said capacitor being connected to the non-inverting terminal of said operational amplifier and having a programmed reference voltage charge stored therein,

wherein said operational amplifier receives and outputs said reference voltage charge which is unaffected by changes in temperature.

2. A circuit as set forth in claim 1, wherein said programmed reference voltage charge stored in said capacitor is constant over increasing time.

3. A circuit as set forth in claim 2, wherein said capacitor is fabricated using a Double Poly MOS Process, said capacitor comprising a first poly layer, a second poly layer, and an isolating layer intervened therebetween.

4. A circuit as set forth in claim 3, wherein said first poly layer corresponds to said floating gate and said second poly layer corresponds to said controlling gate.

5. A circuit as set forth in claim 4, wherein a contact area between said floating gate and said controlling gate is formed having a plurality of bumps so as to decrease a tunneling voltage effect therebetween by increasing an electric field between said floating gate and said controlling gate.