Multi-range current sampling half-bridge output driver

{
  "publication_number": "US6765412B1",
  "country": "US",
  "kind": "B1",
  "title": "Multi-range current sampling half-bridge output driver",
  "abstract": "A current sampling half-bridge output driver capable of driving a wide range of loads using an accurate selection of current sensing resistors. Pluralities of stages are connected in series with the current sensing resistors from each stage connected in series. A range selector selects the stage appropriate for each current load. The reference resistors for a selected stage includes the current sensing resistor associated with that stage added in series to all current sensing resistors electrically connected between the selected stage and the load. The disclosed circuit avoids switching resistors in and out of the circuit and thereby increases the accuracy of the sensing resistor circuit.",
  "claims": [
    "1. A current sampling output driver for multi-range currents, comprising: a voltage source having first and second terminals; a transduction amplifier; a plurality of stages of current sensing circuits with a plurality of current sensing resistors operatively connected between the first and second terminals; the current sensing resistors operatively connected to the stages of current sensing circuits and the current sensing resistors operatively connected in series between a load and the transduction amplifier; a means for selectively connecting stages of current sensing circuits; and a feedback signal lead operatively connected between the transduction amplifier and the load.",
    "2. The output driver of claim 1 wherein the current sensing circuit is a half-bridge circuit.",
    "3. The output driver of claim 1 wherein the current sensing circuit is a full-bridge circuit.",
    "4. The output driver of claim 1 wherein the transduction amplifier is a differential operational amplifier.",
    "5. The output driver of claim 1 wherein the voltage source is direct current.",
    "6. A current sampling half-bridge output driver for multi-range currents, comprising: a voltage source having first and second terminals; a differential circuit; a plurality of stages of current sensing circuits with a plurality of current sensing resistors operatively connected between the first and second terminals; the current sensing resistors operatively connected to the stages of current sensing circuits and the current sensing resistors operatively connected in series between a load and the differential circuit; a means for selectively electrically connecting stages of current sensing circuits; and a feedback signal lead operatively connected between the transduction amplifier and the load.",
    "7. A current sampling half-bridge output driver for multi-range currents, comprising: a direct current voltage source having first and second terminals; a differential amplifier; a plurality of stages of current sensing half-bridge circuits with a plurality of current sensing resistors operatively connected between the first and second terminals; the current sensing resistors operatively connected to the stages of current sensing half-bridge circuits and the current sensing resistors operatively connected in series between a load and the differential amplifier; a means for selectively electrically connecting stages of current sensing circuits; a feedback signal lead operatively connected between the transduction amplifier and the load; a means for feedback analysis operatively connected to the feedback lead and the means for selectively electrically connecting stages of current sensing half-bridge circuits; and a means for logic control of the current and voltage operatively connected to the feedback lead and the means for selectively electrically connecting stages of the current sensing half-bridge circuits.",
    "8. The output driver of claim 7 wherein the means for logic control of the current and voltage is a pulse width modulator."
  ],
  "description_excerpt": "The present invention relates to a current sampling output driver that is capable of sensing and adjusting to accommodate a wide range of current loads. More specifically, the invention is a half-bridge output driver designed to interface an inductive or capacitive load, typically a motor, to a low voltage logic device in order to detect and control of the speed, power, and torque of a motor.\n\nDC motor performance varies in relation to motor current (I motor), motor torque (M), motor speed (n), and output power (P out), assuming negligible internal friction. The motor current, I motor, is a linear function of the motor torque, M. I motor =ƒ(M), or ΔI motor =ΔM. Increasing current to the motor, I motor, increases the motor's torque. Motor speed, n, is an inverse linear function of the motor torque, M. n=ƒ(M), or Δn=−ΔM. Motor speed, n, increases as motor torque, M, decreases. Finally, the output power, P out, is determined by the applied motor current, I motor, multiplied by the motor generator Electro Motive Force, V EMF. P out =I motor ·V EMF, or P out =I 2 motor ·R. It may therefore be seen that the speed, power, and torque of the motor may all be controlled by controlling either the current or voltage delivered to the motor.\n\nDC motors function as both resistors to supply voltage and current and also as generators, creating a voltage described as “back electro magnetic force” or BackEMF. By placing a relatively small resistor, as sensing resistor, in series with the load, and measuring the voltage across this resistor, it is possible to determine the current through the resistor and thereby to the load.",
  "cpc": [
    "H03K 17/04206",
    "H03K 17/165"
  ],
  "ipc": [
    "H03K 17/042",
    "H03K 19/0175"
  ],
  "assignees": [
    "Sauer Danfoss Inc"
  ],
  "inventors": [
    "Joseph J. Schottler",
    "Dennis A. Burns"
  ],
  "filing_date": "2003-05-01",
  "publication_date": "2004-07-20",
  "grant_date": "2004-07-20",
  "priority_date": "2003-05-01",
  "application_number": "US-42722003-A",
  "family_id": "32681920",
  "cited_by_count": 11,
  "citations": [
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  ]
}