Power supply circuit for a gaseous discharge tube device

• US 4,970,439 A
• Filed: 04/28/1989
• Issued: 11/13/1990
• Est. Priority Date: 04/28/1989
• Status: Expired due to Term

• Current Assignee: Global Traffic Technologies LLC (Vontier Corp.)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Stopa, James L.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Neyzari, Ali
• Application Number:
  US07/345,001
• Time in Patent Office: 564 Days
• Field of Search: 315/241 R, 315/241 P, 315/224, 315/DIG. 7, 315/242, 315/244, 315/245, 315/219, 315/200 A
• US Class Current: 315/241.00R
• CPC Class Codes: H03K 17/04206 in field-effect transistor switches
• CPC Class Codes: H03K 17/6877 the control circuit comprising active elements different from those used in the output circuit
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption
• CPC Class Codes: H03K 3/57 the switching device being a semiconductor device
• CPC Class Codes: H05B 41/32 for single flash operation
• CPC Class Codes: Y10S 315/07 Starting and control circuits for gas discharge lamp using transistors

Abstract

An improved power supply circuit for supplying power to intermittently energized loads, such as gaseous discharge tube devices. Such power supply has a transformer wherein current flow in the primary winding is controlled by a first semiconductor device that in turn is controlled by a second semiconductor device. A feedback circuit coupled to the primary winding provides a signal for turn-off of the first semiconductor device when its turn-off is initiated by the second semiconductor device. A circuit portion connected between the primary winding and the second semiconductor device provides a signal to the second semiconductor device when it initiates a turn-off of the first semiconductor device. Such signal continues operation of the second semiconductor device until the turn-off signal from the feedback circuit is effective to turn-off the first semiconductor device serving to reduce power dissipated in the first semiconductor device.

Claims

1. An improved power supply circuit which includes a transformer having a primary winding, a first semiconductor device in series with the primary winding for controlling current flow in the primary winding, a second semiconductor device connected to the first semiconductive device for controlling the operation of the first semiconductive device and a feedback circuit including a winding coupled to the primary winding and connected to the first semiconductor device providing a signal for turn-off of the first semiconductor device following the initiation of the turn-off of the first semiconductor device by the second semiconductor device, the improvement including:

a circuit portion connected between the primary winding of the transformer and the second semiconductive device for supplying a signal to the second semiconductor device when the second semiconductor device operates to initiate the turn-off of the first semiconductor device to continue such operation of the second semiconductor until the signal from the feedback circuit for turn-off of the first semiconductive device is effective, whereby the speed at which the first semiconductor device is turned-off is enhanced thereby reducing power dissipated in the first semiconductor device.

2. An improved power supply circuit according to claim 1 wherein said circuit portion includes a resistor connected in series with a capacitor.

3. An improved power supply circuit according to claim 1 wherein said second semiconductor device is a transistor having a base electrode with said circuit portion connected to said base electrode.

4. An improved power supply circuit according to claim 3 wherein said circuit portion includes a resistor connected in series with a capacitor.

5. An improved power supply circuit according to claim 1 wherein said first semiconductor device is a field effect transistor having a gate electrode, said second semiconductor device is a transistor having a base electrode and a collection electrode, said gate electrode connected to said collector electrode and said circuit portion connected to said base electrode.

6. An improved power supply circuit according to claim 5 wherein said circuit portion includes a resistor connected in series with a capacitor.