Driving circuit for integrated circuit semiconductor memory

• US 4,176,289 A
• Filed: 06/23/1978
• Issued: 11/27/1979
• Est. Priority Date: 06/23/1978
• Status: Expired due to Term

• Current Assignee: Electronic Memories & Magnetics Corp. (L3Harris Technologies, Inc.)
• Original Assignee: Electronic Memories & Magnetics Corp. (L3Harris Technologies, Inc.)
• Inventors: Leach, George S., O'Connell, Timothy R.
• Primary Examiner(s): Anagnos, Larry N.
• Application Number:
  US05/918,394
• Time in Patent Office: 522 Days
• Field of Search: 307/205, 307/214, 307/251, 307/270, 307/DIG. 1, 307/DIG. 4
• US Class Current: 326/88
• CPC Class Codes: G11C 11/24 using capacitors G11C11/22 takes precedence; using a combination of semiconductor devices and capacitors G11C11/34, e.g. G11C11/40
• CPC Class Codes: G11C 11/419 Read-write [R-W] circuits
• CPC Class Codes: H03K 5/023 using field effect transistors

Abstract

An improved driving circuit is provided especially for use in an integrated circuit semiconductor memory which operates on low power supply voltage, such as 5 volts, the drive circuit employing field effect transistors coupled with bootstrap capacitor devices and responsive to an input pulse for supplying, at its output terminal, a pulse having a peak voltage potential substantially equal to the power supply voltage value despite the inherent threshold voltage drops of the field effect transistors utilized. In the drive circuit, in response to an input pulse, the reference voltage for charged capacitor devices is switched between a first level and a raised second, higher level to place the capacitor devices in series with each other and the raised reference voltage to overdrive an output switch device so as to connect substantially its full power supply voltage to its output terminal during a corresponding output pulse.

Claims

1. A drive circuit operable in response to applied first and second signals to supply to an output terminal a signal of predetermined potential substantially equal to a supply potential, said drive circuit comprising:

a first charging circuit including a first capacitor and a first switchable depletion mode field effect device selectively switchable conductive for charging said first capacitor to the supply potential;

a second charging circuit including a second capacitor and a second switchable depletion mode field effect device selectively switchable conductive for charging said second capacitor to the supply potential;

an output circuit, including an output field effect device switch receiving the supply potential and drivable for coupling the supply potential to the output terminal; and

a control circuit coupled to said first and second charging circuits, said control circuit being responsive to the first signal for switching conductive said first and second switchable depletion mode devices to charge said first and second capacitors to the supply potential,

said control circuit being operable in response to the second signal for switching said first and second depletion mode devices non-conductive and for raising the base reference potential of said second capacitor towards the supply potential,

said control circuit being further responsive to the second signal for serially interconnecting and cascading said first and second capacitors to apply the combination of their individual potentials and the raised base reference potential to said output circuit for overdriving said output switch with a predetermined portion of the combined potentials to couple substantially the full supply potential to the output terminal.

2. The drive circuit of claim 1 wherein said control circuit applies to said output circuit a combined potential substantially equal to triple the supply potential for overdriving the output switch with a portion of the combined potentials substantially equal to twice the supply potential.

3. The drive circuit of claim 2 wherein said output circuit includes an output field effect transistor having its drain electrode connected to said second capacitor and its source electrode connected to drive said output switch, said control circuit in response to the second signal applying a combined potential substantially equal to triple the supply potential to the gate of said output field effect transistor to render said transistor highly conductive to apply therethrough the combination of the individual potentials of said second capacitor and the raised base reference potential to overdrive said output switch.

4. The drive circuit of claim 1 wherein said control circuit includes a continually resistively conducting depletion mode field effect device connected between said first capacitor and said output circuit to normally maintain a potential difference therebetween which permits said first capacitor to be charged to the supply potential without activating the output circuit.

5. The drive circuit of claim 4 wherein said control circuit in response to the first signal establishes a current path outlet for current passing through said continually resistively conducting depletion mode device and in response to the second signal removes said current path outlet, whereby the potential applied to said output circuit rises in response to the second signal.