Circuit for loss-less diode equivalent

• US 6,870,417 B2
• Filed: 04/09/2003
• Issued: 03/22/2005
• Est. Priority Date: 04/04/2003
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens Milltronics Process Instruments, Inc. (Siemens AG)
• Inventors: Mercier, Claude
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): Nguyen, Hai L.
• Application Number:
  US10/409,048
• Publication Number:
  US 20040201413A1
• Time in Patent Office: 713 Days
• Field of Search: 327/493, 327/104, 327/343, 327419-421, 327/427, 327/524, 327/531, 327/538, 327/541, 327/543, 327/583, 327/584
• US Class Current: 327/493
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/302 in field-effect transistor switches

Abstract

A loss-less diode equivalent circuit which functions to reduce and eliminate the forward bias voltage or drop associated with conventional diodes. The loss-less diode comprises a reverse connected MOSFET device which is configured with a clamping circuit and coupled to an input stage. The drain is coupled to the input stage which receives an input signal. The source of the MOSFET device provides an output port for charging a capacitor in a conduction or on state.

Claims

1. A loss-less diode circuit comprising:

(a) an input stage having an input port and an output node, said input port being adapted for receiving an input signal;

(b) a diode equivalent circuit having an input, said input being coupled to said output node, said diode equivalent circuit including a reverse connected field effect transistor having a first terminal forming said input coupled to said output node, a second terminal forming an output, and a third terminal providing a control input, said field effect transistor having a diode providing a conduction path between said first and said second terminals when said field effect transistor is in an off state, and said control input being coupled to said input port through a transistor;

(c) said diode equivalent circuit including a clamping device, said clamping device being coupled to the third terminal of said field effect transistor and providing a clamping voltage to protect said third terminal; and

(d) the second terminal of said field effect transistor providing an output port for said circuit, and said output port being adapted for coupling to a capacitor and said capacitor being charged by the input signal applied to said input port.

2. The loss-less diode circuit as claimed in claim 1, wherein said input stage comprises a filter circuit including a bipolar junction transistor having a collector, an emitter and a base, said collector forming said input port, said emitter forming said output node, and said base being coupled to said collector through a resistor, and said base being coupled to signal ground through a capacitor.

3. The loss-less diode circuit as claimed in claim 1, wherein said field effect transistor comprises a P-channel MOSFET device having a drain, a source and a gate, and said first terminal comprises the drain, the second terminal comprises the source, and the third terminal comprises the gate, and said diode comprises an internal diode coupled across the drain and the source of said MOSFET device.

4. The loss-less diode circuit as claimed in claim 3, wherein said clamping device comprises a Zener diode and the transistor, said Zener diode having a cathode coupled to the source of said MOSFET device, and an anode coupled to the gate of said MOSFET device, and said transistor is a bipolar junction transistor having an emitter coupled to said cathode, a collector coupled to said anode and to the gate of said MOSFET device, and a base coupled to said input port through a resistor, and the emitter of said bipolar junction transistor providing said output port.

5. The loss-less diode circuit as claimed in claim 3, wherein said clamping device comprises a bipolar junction transistor having a collector, an emitter and a base, the emitter being coupled to the gate of said MOSFET device, and the collector being coupled to the source of said MOSFET device, and said bipolar junction transistor being operated in reverse mode, and said collector forming said output port.

6. The loss-less diode circuit as claimed in claim 5, wherein said input stage comprises a bipolar junction transistor having an emitter, a collector and a base, said emitter forming said input port, said base being coupled to signal ground, and said collector forming said output node, and said emitter being coupled to the base of said bipolar junction transistor for said clamping device.

7. A loss-less diode circuit comprising:

(a) an input stage having an input port and an output node, said input port being adapted for receiving an input signal;

(b) a diode equivalent circuit having an input, said input being coupled to said output node, said diode equivalent circuit including a reverse connected MOSFET device, said MOSFET device having a drain, a source and a gate, said drain being coupled to said output node, said gate being coupled to signal ground through a resistor, and said MOSFET device including an internal diode coupled between said drain and said source and providing a conduction path when said MOSFET device is in an off state;

(c) said diode equivalent circuit including a Zener diode and a bipolar junction transistor, said Zener diode having a cathode and an anode, said cathode being coupled to the source of said MOSFET device, said anode being coupled to the gate of said MOSFET device, and said bipolar junction transistor having an emitter, a collector and a base, said emitter being coupled to said cathode and the source of said MOSFET device, said collector being coupled to said anode and the gate of said MOSFET device and said base being coupled to said input port through a resistor; and

(d) the source of said MOSFET device providing an output port for said circuit, and said output port being adapted for coupling to a capacitor and said capacitor being charged by the input signal applied to said input port.

8. The loss-less diode circuit as claimed in claim 7, wherein said MOSFET device comprises a P-channel device.

9. The loss-less diode circuit as claimed in claim 8, wherein said Zener diode comprises a bipolar junction transistor having a collector, an emitter and a base, said collector and said base being coupled together to form a diode connected transistor.

10. The loss-less diode circuit as claimed in claim 9, wherein said diode-connected transistor comprises a PNP junction transistor.

11. A loss-less diode circuit comprising:

(a) an input stage having an input port and an output node, said input port being adapted for receiving an input signal;

(b) a diode equivalent circuit having an input, said input being coupled to said output node, said diode equivalent circuit including a reverse connected MOSFET device, said MOSFET device having a drain, a source and a gate, said drain being coupled to said output node, said gate being coupled to signal ground through a resistor, and said MOSFET device including an internal diode coupled between said drain and said source;

(c) said diode equivalent circuit including a first bipolar junction transistor, said first bipolar junction transistor having an emitter, a collector and a base, said collector being coupled to the source of said MOSFET device, said emitter being coupled to the gate of said MOSFET device and said base being coupled to the input port through a resistor; and

(d) the source of said MOSFET device providing an output port for said circuit, and said output port being adapted for coupling to a capacitor and said capacitor being charged by the input signal applied to said input port.

12. The loss-less diode circuit as claimed in claim 11, wherein said input stage comprises a filter circuit including a second bipolar junction transistor having a collector, an emitter and a base, said collector forming said input port, said emitter forming said output node, and said base being coupled to said collector through a resistor, and said base being coupled to signal ground through a capacitor.

13. The loss-less diode circuit as claimed in claim 11, wherein said MOSFET device comprises a P-channel device.

14. The loss-less diode circuit as claimed in claim 13, wherein said first bipolar junction transistor comprises a PNP device.

15. The loss-less diode circuit as claimed in claim 14, wherein said input stage comprises a second bipolar junction transistor having an emitter, a collector and a base, said emitter forming said input port, said base being coupled to signal ground, and said collector forming said output node.

16. A loss-less diode circuit comprising:

(a) an input stage having an input port and an output node, said input port being adapted for receiving an input signal;

(b) a diode equivalent circuit having an input, said input being coupled to said output node, said diode equivalent circuit including a reverse connected field effect transistor having a first terminal forming said input coupled to said output node, a second terminal forming an output, and a third terminal providing a control input, said field effect transistor having a diode providing a conduction path between said first and said second terminals when said field effect transistor is in an off state;

(c) said diode equivalent circuit including a clamping device, said clamping device being coupled to the third terminal of said field effect transistor and providing a clamping voltage to protect said third terminal;

(d) the second terminal of said field effect transistor providing an output port for said circuit, and said output port being adapted for coupling to a capacitor and said capacitor being charged by the input signal applied to said input port;

(e) said field effect transistor comprising a P-channel MOSFET device having a drain, a source and a gate, and said first terminal comprises the drain, said second terminal comprises the source, and said third terminal comprises the gate, and said diode comprises an internal diode coupled across the drain and the source of said MOSFET device;

(f) said clamping device comprises a first bipolar junction transistor having a first collector, a first emitter and a first base, the first emitter being coupled to the gate of said MOSFET device, and the first collector being coupled to the source of said MOSFET device, and said first bipolar junction transistor being operated in reverse mode, and said first collector forming said output port; and

(g) said input stage comprises a second bipolar junction transistor having a second emitter, a second collector and a second base, said second emitter forming said input port, said second base being coupled to signal ground, and said second collector forming said output node, and said second emitter being coupled to the first base of said first bipolar junction transistor for said clamping device.