WO2006090333A1 - Current sense fet - Google Patents

Current sense fet Download PDF

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Publication number
WO2006090333A1
WO2006090333A1 PCT/IB2006/050568 IB2006050568W WO2006090333A1 WO 2006090333 A1 WO2006090333 A1 WO 2006090333A1 IB 2006050568 W IB2006050568 W IB 2006050568W WO 2006090333 A1 WO2006090333 A1 WO 2006090333A1
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WO
WIPO (PCT)
Prior art keywords
current
source
fet
sense
gate
Prior art date
Application number
PCT/IB2006/050568
Other languages
French (fr)
Inventor
Keith Heppenstall
Ian Kennedy
Ronald Fuller
Original Assignee
Nxp B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nxp B.V. filed Critical Nxp B.V.
Publication of WO2006090333A1 publication Critical patent/WO2006090333A1/en

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/34—DC amplifiers in which all stages are DC-coupled
    • H03F3/343—DC amplifiers in which all stages are DC-coupled with semiconductor devices only
    • H03F3/345—DC amplifiers in which all stages are DC-coupled with semiconductor devices only with field-effect devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/52—Circuit arrangements for protecting such amplifiers
    • H03F1/523—Circuit arrangements for protecting such amplifiers for amplifiers using field-effect devices

Definitions

  • the invention relates to a FET and in particular to a FET which can sense output current.
  • FETs Field effect transistors (FETs), especially Metal Oxide Semiconductor
  • MOSFETs MOSFETs
  • MOSFETs MOSFETs
  • Electronic circuits may also include protection circuits.
  • protection circuits For example,
  • US-4, 958,251 describes a circuit with a pair of MOSFETs and two pairs of zener diodes included in the circuit though not in the current path for protecting the circuit against failure caused by connecting the battery with incorrect polarity.
  • a transistor device comprising: a main field effect transistor with source, gate and drain; a first side terminal connected to the source of the main field effect transistor; a second side terminal connected to the drain of the main field effect transistor; a gate terminal connected to the gate of the main field effect transistor; a sense field effect transistor with a drain connected to the second side terminal, a gate connected to the gate terminal and a source.
  • controlled current source connected to supply current to the source of the sense field effect transistor, the controlled current source having a current supply connected to the gate terminal to supply current from the gate terminal, the controlled current source having control inputs connected to the source of the main FET and the source of the sense FET to control the controlled current source by the difference in voltages between the sources of the sense and main FETs.
  • the controlled current source may track the voltages on the sources of the sense and main transistors to constrain the difference between them to be zero, for example by using a virtual earth circuit. In this way, the circuit can deliver a current sense current on the gate terminal which allows a current sense function with no additional terminals.
  • the main and sense FETs act as reverse polarity protection for the external circuit, preventing current flow from the first side terminal to the second side terminal when the first side terminal is negative with respect to the second side terminal and the gate terminal voltage is close to that of the source (first side terminal).
  • the gate input In normal operation, the gate input would be 'pulled up' to a voltage close to positive supply voltage via a low value current sense resistor. This would bias the main and sense FETs on into hard conduction.
  • the device may be packaged in a housing having exactly three terminals being the gate terminal, the first side terminal and the second side terminal.
  • Such three terminal packages are relatively cheap and assembly of the transistor in the package is well known and straight forward.
  • Such packages are commonly used for power circuits, so no additional redesigning would be required to use the transistor device according to the invention in existing or new designs.
  • the transistor device may further include a current control FET arranged between the drain of the main FET and the second side terminal with the drain of the current control FET being connected to the drain of the main
  • Such an additional transistor allows the current flow from the first terminal to the second terminal to be switched off, for example in a fault condition, when the circuit overheats, or for other reasons.
  • the device may include a temperature sensing diode integrated with the current control FET, the temperature sensing diode being connected between the second side terminal and the gate of the current control FET.
  • a temperature sensing diode integrated with the current control FET, the temperature sensing diode being connected between the second side terminal and the gate of the current control FET.
  • Such diodes have a forward voltage drop that is a function of temperature at a given current, and so can be used to measure the temperature.
  • this diode is a Zener diode connected between the second side terminal and the gate of the current control FET, the diode will protect the current control FET gate against electrostatic discharge.
  • the gate of the current control FET may be connected to an internal control circuit. This can, for example, measure the voltage across the temperature protection diode by measuring the voltage across the diode when a small forward current flows it. The control FET will clearly be turned off during this procedure, as its gate source voltage will be negative. The internal control circuit can then delay or prevent the switch on of the current control FET to manage current flow in the event of the temperature rising above a predetermined value representing the circuit overheating.
  • the current control FET may alternatively be connected to and controlled by a current control gate terminal. In this way, temperature sensing and control functions may be provided externally of the device.
  • the controlled current source may be a virtual earth amplifier including a differential amplifier with differential inputs connected to the sources of the sense and main field effect transistors, and an output connected to supply current to the source of the sense field effect transistor.
  • the controlled current circuit may further include a transistor to supply current to the source of the sense field effect transistor, the current supply transistor being controlled by the output of the differential amplifier.
  • the sense and main FETs may be integrated on a single monolithic semiconductor substrate, optionally together with the current control FET where present. In embodiments, all components including the FETs and the controlled current source are monolithically integrated. Alternatively, some or all of the components may be formed on separate substrates and integrated as a multi-chip module.
  • Figure 1 shows a circuit diagram of a first embodiment of the invention
  • Figure 2 shows results obtained using the first embodiment
  • Figure 4 shows a circuit diagram of a second and a third embodiment of the invention.
  • a transistor device includes housing 2 with three terminals, a gate terminal 4, a second side terminal 6 and a first side terminal 8.
  • a single integrated FET 10 is provided on a single substrate, which has two FETs, a main FET 12 and a sense FET 14. Both the main and the sense FETs 12,14 are integrated together and share a common gate 16, a common drain 18, but have separate sources 20,22, a main source 20 and a sense source 22.
  • the main and sense FETs are like FETs but the main FET has a much higher area and so for any given gate voltage passes a much higher current.
  • the common gate 16 is connected to the gate terminal 4 and the common drain to the second side terminal 6.
  • FET is connected to the first side terminal 8.
  • a controlled current source 30 is also provided in the housing.
  • the controlled current source 30 is provided on a separate substrate to the integrated FET 10.
  • the controlled current source has a pair of differential inputs 32,34, a current input 36 connected to the gate terminal 4 and a current output 38 connected to the source 22 of the sense FET.
  • the controlled current source includes a differential operational amplifier 40 with differential inputs 32,34 as the inputs, the differential amplifier having its output connected through resistor 42 to the base of bipolar transistor 44.
  • the collector of bipolar transistor 44 is connected to the current input 36 and the emitter is connected through resistor 46 to the sense source 22.
  • the operational amplifier is powered by being connected across between the source and gate terminals as shown.
  • the circuit may be connected as a low side circuit by connecting source terminal 8 as the output to an external circuit.
  • the controlled current source 30 acts as a virtual earth amplifier aiming to keep the voltage across its differential inputs 32,34 close to zero and accordingly to keep the voltage at the sense source 22 equal to that on the main source 20. In this state, the current through the sense FET 14 is a fixed proportion of that through the main FET 12.
  • This current is supplied from gate terminal 4 and accordingly the gate terminal effectively provides a current sense output without requiring an additional current sense pin on the package. This reduces complexity and hence cost. Further, the device can be included in a standard three terminal power FET packages and in high current three terminal packages such as
  • a small external resistor in series with the gate terminal (4) is still required to develop a voltage proportional to the sense current, however, as the current it carries is only a small proportion of the total device current, a small, accurate, low cost and low power resistor may be used rather than the large, expensive, high power resistor that would be needed if the total current were to be sensed. Cost, PCB area requirement and power dissipation are therefore reduced.
  • the circuit provides reverse polarity protection to an external circuit which may be useful where it is possible for the device to face power supplies of the wrong polarity, for example where a battery might be connected in the wrong polarity.
  • Figures 2 and 3 show measured results on a prototype of the embodiment of Figure 1.
  • resistor 42 is 1 K
  • transistor 44 is a BC108
  • the operational amplifier is on a LM392 chip.
  • Figure 2 shows the gate (sense) current as a function of drain current.
  • Figure 3 shows the same information presented as a ratio of drain to gate current as a function of drain current. As will be seen, the ratio is substantially constant over a wide range of drain currents, up to 5OA, showing that the approach provides a sense current that is a good measure of total drain current.
  • FIG. 4 A second embodiment is shown in Figure 4.
  • a further current control FET 50 is provided with its drain connected to the drain of the main FET 12 and its source connected to the second side terminal 6
  • the current control FET 50 may be integrated on the same substrate as the main FET 12 and the sense FET 14.
  • the gate of the current control FET 50 is connected to a separate current control gate terminal 52.
  • a Zener protection diode 54 is provided between the gate terminal 52 and the second side terminal 6, with its cathode connected to the gate terminal 52 and the anode to the second side terminal 6.
  • a series connected chain of such Zener protection diodes may alternatively be used
  • the current control FET provides the ability to control the current flow from terminal 8 to terminal 6 in the device.
  • Zener protection diode 54 is integrally formed on the same substrate as main FET 12, sense FET 14 and control FET 50, and its temperature coefficient can be used to measure the temperature of these FETs.
  • a current supply and a voltage sense device may be provided on current control gate terminal 52 and if the temperature rises too high appropriate action may be taken, for example by controlling the current control FET, maintaining it in the off state and so allowing the device to cool.
  • circuits may be monolithically integrated, provided in a multi-chip package, or even use discrete components.
  • the invention is of particular use in automobile circuits, and other battery-powered applications, though it may be applied in any application where reverse polarity protection and/or current monitoring is required, The skilled person will realise that the invention can be applied to p-type as well as n-type FETs, and also to high-side as well as low-side applications.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Measurement Of Current Or Voltage (AREA)

Abstract

A device includes a main field effect transistor (10) and a sense field effec transistor (12) with common drain and common gate. A controlled current source (30) supplies current to the source (22) of the sense field effect transistor. The current supply of the controlled current source (30) comes from gate terminal 4. The controlled current source (30) has differential inputs (32,34) connected to the source (20) of the main FET and the source ( 22) of the sense FET. The control current source (20) targets a zero voltage between its differential inputs and hence targets a sense current that is a fixed, small proportion of the main current through the source of the main FET (10) . This current is supplied from gate terminal 4 providing a current sense function in a three terminal ( 4,6,8) package.

Description

DESCRIPTION
CURRENT SENSE FET
The invention relates to a FET and in particular to a FET which can sense output current.
Field effect transistors (FETs), especially Metal Oxide Semiconductor
FETs (MOSFETs) are well known transistors. It is often useful to have a current sense output. This can be done using a sense resistor and a separate current sense output. However, the resistor adds complexity, cost and power loss.
Electronic circuits may also include protection circuits. For example,
US-4, 958,251 describes a circuit with a pair of MOSFETs and two pairs of zener diodes included in the circuit though not in the current path for protecting the circuit against failure caused by connecting the battery with incorrect polarity.
According to the invention, there is provided a transistor device, comprising: a main field effect transistor with source, gate and drain; a first side terminal connected to the source of the main field effect transistor; a second side terminal connected to the drain of the main field effect transistor; a gate terminal connected to the gate of the main field effect transistor; a sense field effect transistor with a drain connected to the second side terminal, a gate connected to the gate terminal and a source. a controlled current source connected to supply current to the source of the sense field effect transistor, the controlled current source having a current supply connected to the gate terminal to supply current from the gate terminal, the controlled current source having control inputs connected to the source of the main FET and the source of the sense FET to control the controlled current source by the difference in voltages between the sources of the sense and main FETs.
The controlled current source may track the voltages on the sources of the sense and main transistors to constrain the difference between them to be zero, for example by using a virtual earth circuit. In this way, the circuit can deliver a current sense current on the gate terminal which allows a current sense function with no additional terminals.
The main and sense FETs act as reverse polarity protection for the external circuit, preventing current flow from the first side terminal to the second side terminal when the first side terminal is negative with respect to the second side terminal and the gate terminal voltage is close to that of the source (first side terminal).
In normal operation, the gate input would be 'pulled up' to a voltage close to positive supply voltage via a low value current sense resistor. This would bias the main and sense FETs on into hard conduction.
The device may be packaged in a housing having exactly three terminals being the gate terminal, the first side terminal and the second side terminal. Such three terminal packages are relatively cheap and assembly of the transistor in the package is well known and straight forward. Such packages are commonly used for power circuits, so no additional redesigning would be required to use the transistor device according to the invention in existing or new designs.
The transistor device may further include a current control FET arranged between the drain of the main FET and the second side terminal with the drain of the current control FET being connected to the drain of the main
FET and the source of the current control FET being connected to the second side terminal. Such an additional transistor allows the current flow from the first terminal to the second terminal to be switched off, for example in a fault condition, when the circuit overheats, or for other reasons.
The device may include a temperature sensing diode integrated with the current control FET, the temperature sensing diode being connected between the second side terminal and the gate of the current control FET. Such diodes have a forward voltage drop that is a function of temperature at a given current, and so can be used to measure the temperature.
If this diode is a Zener diode connected between the second side terminal and the gate of the current control FET, the diode will protect the current control FET gate against electrostatic discharge.
The gate of the current control FET may be connected to an internal control circuit. This can, for example, measure the voltage across the temperature protection diode by measuring the voltage across the diode when a small forward current flows it. The control FET will clearly be turned off during this procedure, as its gate source voltage will be negative. The internal control circuit can then delay or prevent the switch on of the current control FET to manage current flow in the event of the temperature rising above a predetermined value representing the circuit overheating. The current control FET may alternatively be connected to and controlled by a current control gate terminal. In this way, temperature sensing and control functions may be provided externally of the device.
The controlled current source may be a virtual earth amplifier including a differential amplifier with differential inputs connected to the sources of the sense and main field effect transistors, and an output connected to supply current to the source of the sense field effect transistor.
The controlled current circuit may further include a transistor to supply current to the source of the sense field effect transistor, the current supply transistor being controlled by the output of the differential amplifier. The sense and main FETs may be integrated on a single monolithic semiconductor substrate, optionally together with the current control FET where present. In embodiments, all components including the FETs and the controlled current source are monolithically integrated. Alternatively, some or all of the components may be formed on separate substrates and integrated as a multi-chip module. For a better understanding of the invention embodiments will now be described, purely by way of example, with reference to the accompanying drawings, in which:
Figure 1 shows a circuit diagram of a first embodiment of the invention; Figure 2 shows results obtained using the first embodiment;
Figure 3 shows further results obtained using the first embodiment; and
Figure 4 shows a circuit diagram of a second and a third embodiment of the invention.
Referring to Figure 1 , a transistor device according to the invention includes housing 2 with three terminals, a gate terminal 4, a second side terminal 6 and a first side terminal 8.
A single integrated FET 10 is provided on a single substrate, which has two FETs, a main FET 12 and a sense FET 14. Both the main and the sense FETs 12,14 are integrated together and share a common gate 16, a common drain 18, but have separate sources 20,22, a main source 20 and a sense source 22. The main and sense FETs are like FETs but the main FET has a much higher area and so for any given gate voltage passes a much higher current. The common gate 16 is connected to the gate terminal 4 and the common drain to the second side terminal 6. The main source 20 of the main
FET is connected to the first side terminal 8.
A controlled current source 30 is also provided in the housing. In this embodiment the controlled current source 30 is provided on a separate substrate to the integrated FET 10.
The controlled current source has a pair of differential inputs 32,34, a current input 36 connected to the gate terminal 4 and a current output 38 connected to the source 22 of the sense FET.
The controlled current source includes a differential operational amplifier 40 with differential inputs 32,34 as the inputs, the differential amplifier having its output connected through resistor 42 to the base of bipolar transistor 44. The collector of bipolar transistor 44 is connected to the current input 36 and the emitter is connected through resistor 46 to the sense source 22.
The operational amplifier is powered by being connected across between the source and gate terminals as shown. In use, the circuit may be connected as a low side circuit by connecting source terminal 8 as the output to an external circuit.
The controlled current source 30 acts as a virtual earth amplifier aiming to keep the voltage across its differential inputs 32,34 close to zero and accordingly to keep the voltage at the sense source 22 equal to that on the main source 20. In this state, the current through the sense FET 14 is a fixed proportion of that through the main FET 12.
This does assume that the current consumption of the control circuit, especially the differential amplifier 40 which has voltage supply inputs connected between the gate terminal 4 and the first side terminal 8, is very much less than the source FET current. In practice, this will be the case with power FETs.
This current is supplied from gate terminal 4 and accordingly the gate terminal effectively provides a current sense output without requiring an additional current sense pin on the package. This reduces complexity and hence cost. Further, the device can be included in a standard three terminal power FET packages and in high current three terminal packages such as
SOT696.
A small external resistor in series with the gate terminal (4) is still required to develop a voltage proportional to the sense current, however, as the current it carries is only a small proportion of the total device current, a small, accurate, low cost and low power resistor may be used rather than the large, expensive, high power resistor that would be needed if the total current were to be sensed. Cost, PCB area requirement and power dissipation are therefore reduced. The circuit provides reverse polarity protection to an external circuit which may be useful where it is possible for the device to face power supplies of the wrong polarity, for example where a battery might be connected in the wrong polarity.
Figures 2 and 3 show measured results on a prototype of the embodiment of Figure 1. In the prototype, resistor 42 is 1 K, resistor 46 100Ω, transistor 44 is a BC108 and the operational amplifier is on a LM392 chip.
Similar components are likely to be integrated together on common substrate in a commercial version of the same device.
Figure 2 shows the gate (sense) current as a function of drain current. Figure 3 shows the same information presented as a ratio of drain to gate current as a function of drain current. As will be seen, the ratio is substantially constant over a wide range of drain currents, up to 5OA, showing that the approach provides a sense current that is a good measure of total drain current.
A second embodiment is shown in Figure 4. In this arrangement, a further current control FET 50 is provided with its drain connected to the drain of the main FET 12 and its source connected to the second side terminal 6
(named with respect to the main FET 20). The current control FET 50 may be integrated on the same substrate as the main FET 12 and the sense FET 14.
The gate of the current control FET 50 is connected to a separate current control gate terminal 52. A Zener protection diode 54 is provided between the gate terminal 52 and the second side terminal 6, with its cathode connected to the gate terminal 52 and the anode to the second side terminal 6. A series connected chain of such Zener protection diodes may alternatively be used The current control FET provides the ability to control the current flow from terminal 8 to terminal 6 in the device.
In a third embodiment, the single Zener diode or chain of Zener diodes is used as a temperature sensing element. Thus, referring to Figure 4, Zener protection diode 54 is integrally formed on the same substrate as main FET 12, sense FET 14 and control FET 50, and its temperature coefficient can be used to measure the temperature of these FETs. A current supply and a voltage sense device may be provided on current control gate terminal 52 and if the temperature rises too high appropriate action may be taken, for example by controlling the current control FET, maintaining it in the off state and so allowing the device to cool.
The skilled person will be able to design many modifications of these embodiments. The circuits may be monolithically integrated, provided in a multi-chip package, or even use discrete components.
The invention is of particular use in automobile circuits, and other battery-powered applications, though it may be applied in any application where reverse polarity protection and/or current monitoring is required, The skilled person will realise that the invention can be applied to p-type as well as n-type FETs, and also to high-side as well as low-side applications.

Claims

1. A transistor device, comprising: a main field effect transistor (12) with source (20), gate (16) and drain (18); a first side terminal (8) connected to the source (20) of the main field effect transistor; a second side terminal (6) connected to the drain (18) of the main field effect transistor; a gate terminal (4) connected to the gate (16) of the main field effect transistor; a sense field effect transistor (14) with a drain connected to the second side terminal (6), a gate connected to the gate terminal (4) and a source (22); and a controlled current source (30) connected to supply current to the source of the sense field effect transistor, the controlled current source having a current supply (36) connected to the gate terminal (4) to supply current from the gate terminal, the controlled current source having control inputs (32,34) connected to the source (20) of the main FET and the source (22) of the sense FET to control the controlled current source by the difference in voltages between the sources (20,22) of the sense and main FETs.
2. A transistor device according to claim 1 further comprising a current control FET (50) arranged between the drain (18) of the main FET and the second side terminal (6) with the drain of the current control FET (50) being connected to the drain of the main FET (12) and the source of the current control FET being connected to the second side terminal (6).
3. A transistor device according to claim 2 further comprising a temperature sensing diode or diode network (54) integrated with the main FET
(12) and/or the current control FET (50) for sensing the temperature of the associated FET or FETs, the or each temperature sensing diode being connected between the second side terminal and the gate of the current control FET (50).
4. A transistor according to claim 3 wherein the temperature sensing diode (54) is a Zener ESD protection diode for providing ESD protection.
5. A transistor device according to claim 2 further comprising a Zener ESD protection diode (54) connected between the second side terminal and the gate of the current control FET.
6. A transistor device according to any of claims 2 to 5 further comprising a current control gate terminal (52) wherein the current control FET 50 has a gate connected to the current control gate terminal (52).
7. A transistor device according to claim 1 further comprising a housing (2) having exactly three terminals being the gate terminal (4), the first side terminal (8) and the second side terminal 6.
8. A transistor device according to any preceding claim wherein the controlled current source (30) is a virtual earth amplifier including a differential amplifier (40) with differential inputs (32,34) connected to the sources (20,22) of the sense and main field effect transistors and further including an output (38) connected to supply current to the source (22) of the sense field effect transistor.
9. A transistor device according to claim 8 wherein the controlled current circuit further includes a current supply transistor (44) to supply current to the source (22) of the sense field effect transistor, the current supply transistor (44) being controlled by the output of the differential amplifier (40).
10. A transistor device according to any preceding claim wherein the FETs (12, 14, 50) are integrated on a single monolithic substrate.
PCT/IB2006/050568 2005-02-24 2006-02-22 Current sense fet WO2006090333A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP05101409.0 2005-02-24
EP05101409 2005-02-24

Publications (1)

Publication Number Publication Date
WO2006090333A1 true WO2006090333A1 (en) 2006-08-31

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2843496A1 (en) * 2013-08-30 2015-03-04 Nxp B.V. Current control circuit with current sense FETs in parallel

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044313A (en) * 1976-12-01 1977-08-23 Rca Corporation Protective network for an insulated-gate field-effect (IGFET) differential amplifier
US5537078A (en) * 1995-03-31 1996-07-16 Linear Technology Corporation Operational amplifier with JFET inputs having low input bias current and methods for using same
DE19841443A1 (en) * 1998-09-10 2000-03-16 Siemens Ag Circuitry protected against reverse polarity to sense load current
DE10129550A1 (en) * 2001-06-19 2003-01-16 Hella Kg Hueck & Co Electronic protection circuit for automobile electronics, has source-drain path of MOSFET switched into conduction dependent on onboard network voltage polarity
US20030081365A1 (en) * 2001-10-26 2003-05-01 Qing He Power supply reverse bias protection circuit for protecting both analog and digital devices coupled thereto

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044313A (en) * 1976-12-01 1977-08-23 Rca Corporation Protective network for an insulated-gate field-effect (IGFET) differential amplifier
US5537078A (en) * 1995-03-31 1996-07-16 Linear Technology Corporation Operational amplifier with JFET inputs having low input bias current and methods for using same
DE19841443A1 (en) * 1998-09-10 2000-03-16 Siemens Ag Circuitry protected against reverse polarity to sense load current
DE10129550A1 (en) * 2001-06-19 2003-01-16 Hella Kg Hueck & Co Electronic protection circuit for automobile electronics, has source-drain path of MOSFET switched into conduction dependent on onboard network voltage polarity
US20030081365A1 (en) * 2001-10-26 2003-05-01 Qing He Power supply reverse bias protection circuit for protecting both analog and digital devices coupled thereto

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2843496A1 (en) * 2013-08-30 2015-03-04 Nxp B.V. Current control circuit with current sense FETs in parallel
CN104426515A (en) * 2013-08-30 2015-03-18 恩智浦有限公司 Current Control Circuit, Module And Soft Starting Circuit
US9397569B2 (en) 2013-08-30 2016-07-19 Nxp B.V. Current control circuit with in parallel transistor modules

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