Rapidly-responding diode detector with temperature compensation

• US 6,262,630 B1
• Filed: 06/04/1999
• Issued: 07/17/2001
• Est. Priority Date: 06/04/1999
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Eriksson, Hans
• Primary Examiner(s): Shingleton, Michael B
• Application Number:
  US09/326,764
• Time in Patent Office: 774 Days
• Field of Search: 330/129, 330/140, 330/143, 330/289, 455/126, 455/116, 455/127, 327/50, 327/332, 327/562, 327/563, 329/352
• US Class Current: 330/129
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

A diode detector that is stable and linear over a wide range of variations in both temperature and power supply voltage and can be used to regulate a.c. signals produced by devices that are responsive to control signals includes a detector diode and a first resistor in series, a capacitor connected between the junction of first resistor and the detector diode and a reference potential, and a compensator diode and a second resistor in series with each other and with the detector diode and first resistor. An input a.c. signal is provided to a first terminal of the detector diode, and a rectified signal is provided at the junction of the detector diode, the first resistor, and the capacitor. The detector diode and the compensator diode have temperature coefficients that are substantially the same, and those diodes have the same polarities. An output buffer amplifier may receive the diode detector'"'"'s output signal, the buffer amplifier having an input bias current that is low relative to an average rectified signal current through the compensator diode. The detector diode and the compensator diode may be Schottky-type diodes and the output buffer amplifier may be a FET-input operational amplifier. A signal generator having a regulated output and employing the diode detector is also disclosed.

Claims

1. A diode detector for generating an output signal that follows an input a.c. signal, comprising:

a detector diode and a first resistor in series, the input a.c. signal being provided to a first terminal of the detector diode, a rectified signal being provided at a second terminal of the detector diode that is connected to a first terminal of the first resistor, the detector diode having a temperature coefficient, and the output signal being provided at a second terminal of the first resistor;

a capacitor having a first terminal connected via a low impedance path to the second terminal of the detector diode and a second terminal connected to a reference potential; and

a compensator diode and a second resistor in series, the compensator diode and second resistor being disposed in series with the detector diode and first resistor, the output signal being provided to one of a first terminal of the compensator diode and a first terminal of the second resistor, and the compensator diode having substantially the same temperature coefficient and the same polarity as the detector diode.

2. The diode detector of claim 1, further comprising an output buffer amplifier, the output signal being provided to an input of the buffer amplifier and the buffer amplifier having an input bias current that is low relative to an average rectified signal current through the compensator diode.

3. The diode detector of claim 2, wherein the detector diode and the compensator diode are Schottky-type diodes and the output buffer amplifier is a FET-input operational amplifier.

4. The diode detector of claim 1, further comprising a reference voltage source disposed in series with the compensator diode and the second resistor, the reference voltage source being accordingly connected to one of a second terminal of the second resistor and a second terminal of the compensator diode, whereby a level of the output signal can be selected.

5. A signal generator having a regulated output, comprising:

an amplifier having an amplifier output signal of a magnitude that is responsive to a control signal;

a coupler that receives the amplifier output signal and generates an a.c. signal that corresponds to the amplifier output signal;

a detector diode and a first resistor in series, the a.c. signal being provided to a first terminal of the detector diode, a rectified signal being provided at a second terminal of the detector diode that is connected to a first terminal of the first resistor, the detector diode having a temperature coefficient, and a detector output signal being provided at a second terminal of the first resistor;

a capacitor having a first terminal connected via a low impedance path to the second terminal of the detector diode and a second terminal connected to a reference potential;

a compensator diode and a second resistor in series, the compensator diode and second resistor being disposed in series with the detector diode and first resistor, the detector output signal being provided to one of a first terminal of the compensator diode and a first terminal of the second resistor, and the compensator diode having substantially the same temperature coefficient and the same polarity as the detector diode; and

an output buffer amplifier, the detector output signal being provided to an input of the output buffer amplifier, the output buffer amplifier having an input bias current that is low relative to an average rectified signal current through the compensator diode, and the control signal being based on an output of the output buffer amplifier.

6. The signal generator of claim 5, wherein the detector diode and the compensator diode are Schottky-type diodes and the output buffer amplifier is a FET-input operational amplifier.

7. The signal generator of claim 5, further comprising a reference voltage source disposed in series with the compensator diode and the second resistor, the reference voltage source being accordingly connected to one of a second terminal of the second resistor and a second terminal of the compensator diode, whereby a level of the detector output signal can be selected.