A transistor device

Abstract

A transistor device includes a transistor and a programmable controller. The controller has an output that controls the operation of the transistor. The controller includes analog computation circuitry and optionally digital computation circuitry that can be used to set the analog computation circuitry. In addition to two connectors for connecting the transistor into an external circuit, the device includes a further connector that provides an input to the controller, and through which the control can be programmed after manufacture. The transistor device can be a discrete component in which the transistor and control circuitry are held in a package, with the three connectors exposed through the package to connect the device to an external circuit.

Description

[0001] The present application relates to a transistor device. In one application, the transistor device can be employed as a power management integrated circuit device.

[0002] In certain applications, such as power integrated circuits, it is desirable to provide both high voltage electronic components and low voltage electrical components on a single semiconductor chip.

[0003] https: / / www.digikey.com / en / articles / techzone / 2016 / may / smart-high- side-drivers-help-meet-tough-new-automotive-standards US2005017688, US2008117125, US9735768 and US2017317001 each disclose an apparatus comprising a transistor operated by a control mechanism.

[0004] According to a first aspect of the present application, there is provided a semiconductor transistor device advantageously discrete, the device comprising: a transistor having first and second terminals for connecting the transistor into an external circuit to control current through the circuit, and a control terminal; a controller circuit, advantageously comprising a computational circuit, the controller circuit having an output connected to the control terminal of the transistor to control operation of the transistor. The controller circuit advantageously comprises at least one input to allow the transistor device to receive control signals and / or data signals from an external source. The controller circuit is advantageously programmable via the at least one input.

[0005] The present application therefore provides a "smart" switch or amplifier which can be used individually or in other combinations in place of a microcontroller. One example application is use in a power adapter circuit.

[0006] Providing a controller circuit which is programmable after manufacture of the device means that a user can select the functionality of the device after manufacture according to the required application.

[0007] The transistor device preferably comprises a bipolar junction transistor having an emitter, a collector and a base. In this way, the controller circuit can have an output connected to the base of the bipolar junction transistor to control operation of the bipolar junction transistor.

[0008] The controller circuit can comprise a computer readable memory. The memory can be used to hold algorithmic information, for example for a multi-step algorithm to be implemented by the controller circuit.

[0009] The computer readable memory can be non-volatile. The computer readable memory is advantageously programmable after its manufacture. The computer readable memory can comprise ROM and / or PROM.

[0010] The controller circuit, e.g. controller computation circuit, can comprise an analog computation circuit. An analog computation circuit is advantageous in that it can operate significantly faster than a digital computation circuit, resolve instantaneously, and can be implemented by significantly fewer transistors.

[0011] However, the controller circuit can comprise a digital computation circuit alone, or more generally advantageously comprise both a digital computation circuit and an analog computation circuit.

[0012] The digital computation circuit can be programmable to select settings of the analog computation circuit. The digital computation circuit can comprise the computer readable memory, which can be one-time programmable memory or reprogrammable memory.

[0013] The controller circuit is advantageously arranged to perform computations using inputs to the controller circuit, and to use results of the computations to control operation of the transistor.

[0014] The controller circuit can have inputs connected to one or both sides of the transistor, e.g. the controller circuit can have inputs connected to the emitter side of the transistor and to the collector side of the transistor to receive indications of current through the transistor and voltage. The controller circuit can receive an indication of voltage at either the collector or the emitter, e.g. relative to ground or some other reference point, e.g. voltage across the emitter and collector.

[0015] Analog signals received through one or both of these inputs can be used by the controller circuit to control the function of the transistor. Analog signals received through one or both of these inputs can be operated on by the analog computation circuit, digital computation circuit, or both, to provide control of the output of the transistor.

[0016] The controller circuit can comprise at least one port to allow the transistor device to receive control signals and / or data signals from external circuitry or devices. The port can be bidirectional to allow the transistor device to also output signals to external devices or circuitry.

[0017] For example, the port can be connected to a capacitor to provide timing functionality. The capacitor can be an integrated component formed on a monolith or an external component.

[0018] The device can comprise a single semiconductor monolith on which the transistor and the controller circuit are fabricated, a housing (e.g. a moulding) which encloses the monolith, and a connector (e.g. a pin connector protruding from the housing) to provide connections to the first and second terminals and, where present, to the port of the controller circuit.

[0019] However, in some embodiments, the transistor and controller circuit can be formed on a separate monolith which is encapsulated in the housing (e.g. moulding). The transistor semiconductor device can be used unencapsulated, i.e. without a housing.

[0020] In various arrangements, the transistor is significantly larger than the electrical components forming the controller circuit (e.g. has a significantly larger lateral length). This allows the transistor to handle relatively large voltages / powers, while the electrical components forming the controller circuit can be relatively small, to keep the overall size of the device to a minimum.

[0021] As such, the transistor can be a relatively high voltage transistor, adapted to be connected into a relatively high voltage circuit via the first and second terminals and to control current through the relatively high voltage circuit, the controller circuit being adapted to operate with relatively low voltage signals. For example, the high voltage circuit can operate at 20V or above, and the low voltage signals can be below 20V, e.g. below 12V.

[0022] The semiconductor region providing the collector or emitter region can be significantly thicker than the semiconductor region providing the base region (in the case of a BJT transistor), advantageously at least ten times thicker, so that the transistor can operate at significantly higher voltages than the relatively small electronic components forming the controller circuit, which are formed in the relatively thin base region, allowing its lateral dimensions to be minimised.

[0023] In another aspect, there is provided a semiconductor device comprising a plurality of transistor devices formed on a single monolith, each transistor device having a first terminal and a second terminal and a control terminal; each of the plurality of transistors having a separate controller circuit associated therewith, each of the separate controller circuits having an output connected to the control terminal of its respective transistor to control operation of its respective transistor. The individual controllers can have a plurality of connections therebetween.

[0024] The application will now be described by way of example with reference to the accompanying drawings in which:

[0025] Figure 1 is a schematic diagram of an NPN bipolar junction transistor device;

[0026] Figure 2 is a schematic diagram of a PNP bipolar junction transistor device;

[0027] Figure 3 is a schematic diagram of a variant NPN bipolar junction transistor device which includes only an analog computing circuit programmed to provide the functionality of a PID controller;

[0028] Figure 4 is a schematic diagram of a further variant NPN bipolar junction transistor device programmed to provide the functionality of a PID controller including both analog and digital computation circuitry;

[0029] Figure 5 is a perspective view of a discrete bipolar junction transistor device;

[0030] Figure 6 is a schematic diagram of an NPN bipolar junction transistor device showing circuitry to power the controller circuitry;

[0031] Figure 7 is a schematic diagram of an NPN transistor device connected to a one-time programming tool to program the digital computation circuitry; Figure 1

[0032] Figure 8 is a schematic diagram of a variant NPN transistor device adapted to be connected to an external debugging tool;

[0033] Figure 9 is a schematic diagram of a circuit including a three-phase brushless DC motor, a battery and drive circuitry;

[0034] Figure 10 is a schematic diagram of a circuit allowing the low-side transistor in a pair of transistors to signal to the high-side transistor in the pair; Figure 9

[0035] Referring to Figure 1 , a schematic diagram of a transistor device 1 is shown, which can be a discrete electronic component or one of a plurality of electronic components of an integrated circuit.

[0036] The device 1 includes an NPN bipolar junction transistor (BJT) 2 formed on a semiconductor chip 3, the BJT 2 having an emitter terminal E, a collector terminal C and a base terminal B.

[0037] Further electronic elements are also formed on the chip 3 to provide a controller circuit 4 having an output 4A connected to the base terminal B of the BJT 2 to control the operation of the BJT 2.

[0038] The controller circuit 4 has ports 7, 7* and 8. The ports 7, 7* are connected across resistors on the emitter side of the BJT 2 to receive an analog signal indicative of the current through the BJT 2.

[0039] The port 8 is connected to the collector side of the BJT 2 to receive an analog signal indicative of the voltage at the collector side of the BJT relative to ground (or some other reference point). In Figure 1 ​​In embodiments of the application, the voltage can be referenced to port 7 to give the voltage across the collector C and emitter E.

[0040] The controller circuit 4 has a further port 9 for receiving signals, for example control signals, from an external source. The further port 9 can act as a bidirectional port for both receiving and transmitting signals from the controller circuit 4.

[0041] The controller circuit 4 comprises an analogue computing circuit 5 and a digital computing circuit 6, which in this embodiment provides the functionality of programmable logic circuitry and one-time programmable memory. The digital circuit 6 is adapted to program the analogue computing circuit 5 (i.e. select its circuit elements or sub-circuits) to provide the required analogue computing functionality.

[0042] The circuit 4 can be arranged such that the analogue signals from one or more of the ports 7*, 8 or 9 can be operated on by the analogue computing circuit 5. In certain arrangements, the digital circuit 6 can be arranged such that the analogue computing machine is able to selectively operate on any of the analogue signals from the first, second and third ports 7*, 8 or 9.

[0043] Alternatively, any of the analogue signals received through the ports 7*, 8 or the further port 9 can be received by the digital computing circuit 6.

[0044] The inclusion of the analogue computing circuit 5 is preferred as it allows fast computation using a relatively small number of integrated electrical components.

[0045] The output of the analogue circuit can provide an output signal via an output 4A of the controller circuit 4 to control the BJT 2. Alternatively, the circuit can be arranged to provide a digital output signal (for example a pulse width modulated signal) via the output 4A to control the BJT 2.

[0046] In addition to selecting which analogue functionality (mathematical operation) is performed by the analogue circuit 5, for example one or more of addition, subtraction, inversion, multiplication, integration, exponentiation, division, logarithm and differentiation. The digital circuit can also be arranged to select between electrical components of the analogue circuit, for example between capacitors of different capacitance or resistors of different resistance, to alter the variable of the computation. In the case where the digital circuit provides CPU functionality, the selection of components can be dynamically made using registers to alter the variable.

[0047] In one variant embodiment where the analogue computing circuit is not used and instead the digital computing circuit is used alone, the algorithm and registers of the digital computing circuit will be used to perform the computation from the inputs through the ports 7*, 8 or 9.

[0048] When analog computation is used, either alone or in combination with digital circuitry, the OTP can be used to store an analog value that can be used as an additional input to a mathematical function applied to an input signal, or can be used to control an analog function such as the period of an analog counter.

[0049] The digital or analog circuitry can include sub-circuits that provide additional functionality, such as timers, temperature sensors.

[0050] In a preferred embodiment, where the device is used as a switch in a power circuit, the lateral dimensions of the BJT are significantly larger than the total lateral dimensions of the controller circuit. The BJT 2 can have lateral dimensions that are at least 4 times larger than the individual electronic components (e.g. transistors, diodes, resistors and capacitors) that form the controller circuit 4.

[0051] The controller circuit 4 can be powered through ports 8 and / or 9, with port 7 connected to a negative supply rail, or alternatively powered through a voltage across ports 8 and 9. Reference is made below to Figure 7 Further details of ways in which this can be achieved are described.

[0052] The resistor between the base and collector of transistor 2 allows the transistor to remain on, and thus the controller circuit 4 to remain powered. In this case, the output 4A of the controller 4 is primarily operating to turn the transistor off when required.

[0053] In some arrangements, the device can include two transistors arranged as a Darlington pair.

[0054] The inclusion of analog computation circuitry allows for a very simple arrangement of the controller circuit 4, avoiding problems associated with ensuring that power supply is maintained to the controller circuit, for example to power volatile memory, digital program counters and registers etc.

[0055] However, in embodiments of the device, for example in embodiments that include volatile memory, a storage capacitor (e.g. a capacitor) can be used to maintain the control powered when no external power is available.

[0056] Figure 2 A variant transistor device 1’ is illustrated that includes a PNP bipolar junction transistor (BJT) 2’. This variant is similar to the device 1 described above, but with the BJT 2’ replaced by a PNP BJT. Figure 1The main difference between the transistor device of figure 1 and the transistor device of figure 2 is that the controller circuit 4' is configured to reference a positive voltage instead of ground to enable the high side switch. In this way, the device has a first port 7', 7' * connected to the emitter side of the BJT 2' to receive an analog signal indicative of the current through the BJT 2', and a second port 8' connected to the collector side of the BJT 2 to receive the voltage at the collector side of the BJT 2' relative to the emitter side (or some other reference point).

[0057] Figure 3 & Figure 4 A variant NPN transistor device is illustrated showing a different example arrangement of the controller circuit.

[0058] In the variant of figure 2, the controller circuit 4 comprises both the analog computation circuit 5 and the digital computation circuit 6. In this arrangement, the analog computation circuit has been programmed to provide the functionality of a PID (Proportional-Integral-Derivative) feedback mechanism, and the digital computation circuit has been programmed to provide the functionality of a digital PID feedback mechanism. Figure 3

[0059] The analog computation circuit 5 can comprise non-volatile analog memory, for example OTP memory, for initial configuration of the circuit or to hold values used in the computation, for example K values (tuning constants Kp, Ki, Kd used in a PID controller), or values used in functions such as a analog clock mechanism.

[0060] The OTP can be composed of degradable electronics. This can be used to provide analog or digital memory elements. In one embodiment, the OTP can be composed of an array of degradable bipolar junction transistors. In a non-degraded state, the transistors are considered to hold a first value, for example 1, and in a degraded state, the transistors are considered to hold a second value, for example 0. The transistors within the array can be selectively degraded to store a program within the memory. In one embodiment, a transistor of the array can be degraded by applying a voltage of opposite polarity to its base terminal of an amplitude that degrades the transistor so as to permanently reduce its gain value. In another variant, the array is composed of polysilicon resistors, an overestimated current is passed through said polysilicon resistors to modify their resistance.

[0061] Because the transistor gain values (in case of using transistors) or resistance values (in case of using resistors) can be degraded in a graduated manner, they are each also able to hold analog values to provide analog memory.

[0062] Figure 4 ​One variant is shown in which the controller circuit includes, in addition to the analogue computation circuit 5 providing the function of the PID feedback mechanism, a digital CPU or programmable logic device and an OTP memory which can be used to select which of the proportional, integral and derivative functions (if not all) are to be applied.

[0063] In the case where the device is a discrete component, as exemplified in Figure 1 or Figure 2 The device includes a housing 10 of any desired shape, which encloses the chip 3 (typically moulded around the chip), an emitter connector 11 connected to the emitter terminal E, and a collector connector 12 connected to the collector terminal C. The connectors are connected to the chip 3 and protrude from the housing 10 to provide means of connecting the discrete device 1 into a circuit. Figure 5

[0064] Figure 5 The device also includes a third connector 13 extending from the housing 10 to provide a connection between the third input 9 of the controller circuit 4 and an external signal source. In a variant design for use where the device can operate without an input signal into the third port 9, the device can be formed with only two pins 11, 12 for connection to the emitter and collector.

[0065] In an alternative arrangement where multiple integrated transistor devices 1 are formed on a single semiconductor die, at least some of the connections between the inputs 9 can be provided by patterned metallisation on the chip.

[0066] Figure 6 is a schematic diagram of an NPN BJT transistor device 1 exemplifying an example power circuit enabling connection of external circuitry through the device to the collector side of the transistor 2, or powering of the controller circuit 4 via the third port 9. In addition, Figure 6 exemplifies a circuit arrangement which allows the device to a) receive an input data signal via port 9 and b) provide an output signal via port 9.

[0067] The device includes a voltage regulator 60 which, in conjunction with a zener diode 61, provides a regulated voltage from the third port 9 to power the controller circuit 4.

[0068] ​Optionally, the controller circuit 4 can be powered from the collector pin via a current regulator 62. Because the voltage between the collector and emitter can be large—for example, greater than 50V, which is to be expected when using this device in a power driver application—there is a risk that the current regulator may overheat. To prevent this, the circuit includes a switch 63, which can be enabled by the controller circuit 4 when the voltage at the collector, as determined via the first port 8, is below a safe voltage.

[0069] The current regulator 62 requires a small amount of power to operate. In high-voltage power applications, it is more feasible to power the current regulator 62 from port 9 shown via connection 64, although in low-power applications, the current regulator can be powered via the collector pin.

[0070] The device also includes a high-impedance measurement element or sub-circuit 65, such as one or more of a resistor, a reverse-biased diode, or an OMP amplifier, which is connected between port 9 and the data input port 66 of the controller circuit 4. The relatively high voltage at port 9 drops across the high-impedance measurement element / sub-circuit 65 to provide a relatively low-voltage data signal at input port 66.

[0071] The device also includes a data output circuit comprising a pull-down resistor 67 located between port 9 and the emitter side of transistor 2, and a transistor switch 68. An output signal from the output data port 69 is used to control transistor 68. To send a data signal from port 9, the signal from the output data port 69 is used to turn on transistor 68, which draws current through port 9. This current can be used to send signals, such as a voltage drop as seen by an external device connected to port 9.

[0072] Figure 7 An example is shown where an external programming tool 20 is connected to allow the user to program the chip 3 using an external computer. Figure 1 Device 1. The output 21 of tool 20 is connected to the third port 9 of controller circuit 4, which acts as a data port when controller circuit 4 is in programming mode. The second output 22 of programming tool 20 is connected to the collector terminal so that clock signals from tool 20 can be received by controller circuit 4 from the collector side through first port 8 to record data into controller circuit 4. The one-time memory function of digital circuitry (although it can have analog circuitry) can then be programmed using conventional techniques.

[0073] As an alternative, data can be transmitted via the second output 22 and port 8, and clock signals can be transmitted via the first output 21 and port 9.

[0074] A variant tool is needed to program the PNP transistor device, which is adapted to take into account the fact that the emitter reference is positive rail, as is the controller 20 and input 9). The programming tool for both NPN and PNP can be combined into a single external programming tool device.

[0075] Figure 8 is a schematic of a variant device 1" which omits the memory but has a number of further pin connectors 13 which connect the additional ports of the controller circuit 4" to an external debugging tool 30. The debugging tool includes a reprogrammable memory which is used by the controller circuit 4" in place of the omitted OTP. The reprogrammable memory of the debugging tool allows the device 1" to be reprogrammed from an external computer, for example a P.C. This provides a convenient means for a programmer to test programs intended for installation on the memory of the earlier described device.

[0076] Optionally, the pin connectors 13 can be used to output signals internal to the controller circuit 4", such as, for example, program counter values, control flags, RAM values (if present) and the like.

[0077] One example application of the devices described above in various aspects is for use as, or as part of, a power management device. For example, the transistor device can form part of a power adapter for an LED lamp arranged to be connected to a mains (e.g. 120V or 240V AC) lighting circuit.

[0078] Another example application is exemplified in Figure 9 which shows a schematic of a drive circuit 40 for powering a three-phase brushless DC motor 43 from a battery 44, composed of six bipolar junction transistor devices, three NPN type 42 and three PNP type 41. The three PNP devices 41 seek their source from the positive rail 45 and the three NPN transistor devices 42 switch to the negative rail (ground) 46. The third port 41A, 42A of each of the devices 41, 42 is connected together to receive a control signal (which can be a pulse width modulated signal or an analogue signal) from a controller or feedback device (e.g. an encoder associated with the motor 43) via an input 47, which in this case can indicate the position and speed of the rotor of the motor.

[0079] A pair of PNP, NPN devices 41, 42 are each associated with a winding W of the motor 43. By suitable programming of each of the devices 41, 42, using the external input signal received via the third port 41A, 42A, the devices 41, 42 will control the current through their respective motor winding to control the motor 43.

[0080] Figure 10 A variant circuit is exemplified which allows communication between the NPN and PNP in a pair of devices without affecting the control signal from input 47. Figure 9

[0081] In the case where the high voltage from positive rail 45 is used to drive motor 43, for example, greater than the control signal from input 47, controller 4 in NPN 42 device can be arranged to signal to PNP 41 via current level shifting to effect switching of PNP device 41.

[0082] The output port 42A of NPN device 42 can be pulled down to the emitter E via transistor 68 of the data output circuit of NPN device 42, thereby reducing the voltage at 42A. A voltage divider circuit created by the resistor arrangement of Rl (in the connection between upper rail 40 and PNP device input 41A) & R2 (in the line between PNP input 41A and NPN input 41A) causes a corresponding voltage change at 41A. This voltage change is detected by the high impedance measurement circuit 65 of PNP 41.

[0083] The resistor R3 between NPN port 42A and control input 47 ensures that the action of pulling output port 42A down to the emitter does not adversely affect the signal received from input 47 which can otherwise affect other devices connected to input 47. The control input 47 ensures that the action of pulling output port 42A down to the emitter does not adversely affect the signal received from input 47 which can otherwise affect other devices connected to input 47.

[0084] This configuration allows NPN 42 to send commands to PNP 41, such as, for example, to provide or change the size of the timing delay between NPN 42 off and PNP 41 on to prevent shorting of supply rails 40 and 46.

[0085] In one variant of the embodiment described above, the BJT 2 can be replaced with a FET, in such an arrangement the output 4A of the controller circuit is connected to the gate terminal of the FET.

[0086] In one variant arrangement, the device can not include one or both of the first and second inputs and can instead be adapted to control the BJT using a signal received through the third port. In variants according to this arrangement, the controller circuit 4 will need to be factory programmed to provide the required functionality.

[0087] It will be appreciated that the above describes only a few example configurations of the analog computing circuit and that the user can select the actual operations performed by the analog computing circuit according to the intended functionality of the transistor device.​

Claims

1. A discrete semiconductor transistor device (1) comprising: a transistor (2) having a first terminal (E) and a second terminal (C) for connecting the transistor (2) into an external circuit for controlling the current through the external circuit, and a control terminal (B); a controller circuit (4) having an output connected to the control terminal (B) of the transistor (2) for controlling the operation of the transistor (2); the controller circuit (4) comprising at least one input (8) to allow the discrete semiconductor transistor device (1) to receive control signals and / or data signals from an external source, and characterized in that the controller circuit comprises an analog computation circuit (5) and a digital computation circuit (6); wherein the analog computation circuit comprises a plurality of sub-circuits, each sub-circuit for performing a different mathematical operation selected from the group consisting of addition, inversion, multiplication, integration, exponentiation, division, logarithm and differentiation; and wherein the digital computation circuit (6) is configurable to program the analog computation circuit (5), including selecting one or more of the sub-circuits to select the mathematical operation.

2. The discrete semiconductor transistor device (1) according to claim 1, wherein the digital computation circuit (6) is one-time programmable.

3. The discrete semiconductor transistor device (1) according to claim 1, wherein the transistor (2) is a high voltage transistor, the high voltage transistor being adapted to be connected into a high voltage circuit via the first and second terminals (E, C) for controlling the current through the high voltage circuit; and wherein the controller circuit (4) operates using relatively low voltage signals.

4. The discrete semiconductor transistor device (1) according to any one of claims 1-3, wherein the transistor (2) and the controller circuit (4) are formed on the same semiconductor monolithic integrated circuit.

5. The discrete semiconductor transistor device (1) according to any one of claims 1-3, wherein the controller circuit (4) has two inputs (7, 7*) connected to the first terminal side of the transistor and to the second terminal side of the transistor, respectively, for receiving an indication of the current through the transistor and an indication of the voltage across the transistor.

6. The discrete semiconductor transistor device (1) according to claim 1, wherein the discrete semiconductor transistor device has a first connector connecting the first terminal of the transistor to a circuit; a second connector for connecting the second terminal of the transistor into a circuit; and a third connector for connecting a further input of the controller circuit to an external signal source.

7. The discrete semiconductor transistor device (1) according to claim 6, wherein the controller circuit (4) is arranged such that a signal received through one of the first, second or third connectors is used as an input for the operation by the analog computation circuit (5), and also to power the digital computation circuit (6).

8. The discrete semiconductor transistor device (1) of claim 6, wherein the device comprises a power circuit, the power circuit being arranged to enable powering of the digital computation circuit from signals received through one or more of the first, second or third connectors.

9. The discrete semiconductor transistor device (1) of any of claims 6-8, comprising a voltage level shift circuit, the voltage level shift circuit being arranged to shift down voltage inputs at any of the first, second or third connectors for input to the controller circuit.

10. The discrete semiconductor transistor device (1) of any of the preceding claims 1-3, wherein the transistor is a bipolar junction transistor.

11. The discrete semiconductor transistor device (1) of claim 10, wherein the controller circuit has an output connected to a base of the bipolar junction transistor to control operation of the bipolar junction transistor; and the controller circuit has inputs connected to an emitter side of the bipolar junction transistor and a collector side of the bipolar junction transistor to receive indications of current and voltage through the bipolar junction transistor.

12. The discrete semiconductor transistor device of claim 1, further comprising a set of electrical components, each electrical component providing a different value of a variable, and wherein the digital circuit is configurable to select an electrical component from the set of electrical components to alter an input variable of the mathematical operation. ​ ​

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