Semiconductor device, electronic apparatus, and vehicle

Abstract

To provide a semiconductor device (signal transmission device) comprising a high-accuracy insulation power supply control function.SOLUTION: A semiconductor device comprises, for example: a first terminal which receives an input signal on a primary side; a second terminal which outputs an output signal to a gate of a first transistor on a secondary side; an insulation signal transmission circuit which transmits an internal signal generated in response to the input signal from the primary side to the secondary side via a first insulation element, outputs the output signal generated in response to the internal signal on the secondary side to the gate of the first transistor and controls ON / OFF; an insulation power supply control circuit which is a control main body of an insulation type power source which generates a secondary side power supply voltage from a primary side power supply voltage and transmits an output feedback signal from the secondary side to the primary side via a second insulation element; a third terminal which receives the primary side power supply voltage and to which a third insulation element of the insulation type power source is connected; a fourth terminal which receives the secondary side power supply voltage; a fifth terminal which receives the output feedback signal on the secondary side; and a sixth terminal to which a gate of a second transistor which is connected to the third insulation element on the primary side is connected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention disclosed in this specification relates to a semiconductor device used as a signal transmission device, and to an electronic device and a vehicle using the same. [Background technology]

[0002] BACKGROUND ART Signal transmission devices having a function of transmitting a pulse signal while insulating a primary circuit system from a secondary circuit system (insulated signal transmission function) have been put to practical use.

[0003] As an example of the related prior art, Patent Document 1 can be mentioned. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-011108 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, some conventional signal transmission devices not only have the original isolated signal transmission function, but also have a function of supplying power from a primary circuit system to a secondary circuit system (isolated power supply control function).

[0006] However, in conventional signal transmission devices, the output feedback control of the flyback power supply is performed based on, for example, the induced voltage appearing in the auxiliary winding of the flyback transformer, so there is room for further improvement in the output accuracy of the flyback power supply.

[0007] In view of the above-described problems discovered by the inventors of the present application, the invention disclosed in this specification aims to provide a signal transmission device having a highly accurate isolated power supply control function, and an electronic device and a vehicle using the same. [Means for solving the problem]

[0008] For example, the signal transmission device disclosed in this specification includes an isolated signal transmission circuit that transmits a pulse signal from a primary circuit system to a secondary circuit system via a first insulating element, and an isolated power supply control circuit that is a control entity of an isolated power supply that generates a second power supply voltage for the secondary circuit system from a first power supply voltage for the primary circuit system, and that transmits an output feedback signal of the isolated power supply from the secondary circuit system to the primary circuit system via a second insulating element.

[0009] Still other features, elements, steps, advantages, and characteristics will become more apparent from the detailed description that follows and the accompanying drawings related thereto. [Effects of the Invention]

[0010] According to the invention disclosed in this specification, it is possible to provide a signal transmission device having a highly accurate isolated power supply control function, and an electronic device and a vehicle using the same. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an electronic device equipped with a signal transmission device. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of an isolated signal transmission circuit. [Figure 3] FIG. 3 is a diagram showing an example of an isolated signal transmission operation. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of an isolated power supply control circuit. [Figure 5] FIG. 5 is a diagram showing a first example of output feedback control. [Figure 6] FIG. 6 is a diagram showing a second example of output feedback control. [Figure 7] FIG. 7 is a diagram showing the exterior of the vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Electronic equipment> 1 is a diagram showing an example of the configuration of an electronic device equipped with a signal transmission device. The electronic device 1 of this example configuration includes a signal transmission device 100 and various discrete components externally attached thereto (a flyback transformer 200, an npn-type insulated gate bipolar transistor Q1, an N-channel MOS field effect transistor N1, a diode D1, a capacitor C1, and resistors R1 and R2).

[0013] The signal transmission device 100 is a semiconductor integrated circuit device (a so-called insulated gate driver IC) that transmits a pulse signal from the primary circuit system 1p to the secondary circuit system 1s while isolating the primary circuit system 1p (Vcc1-GND1 system) from the secondary circuit system 1s (Vcc2-GND2 system) of the electronic device 1, and drives the gate of the transistor Q1 provided in the secondary circuit system 1s.

[0014] In addition, the signal transmission device 100 has multiple external terminals (in this figure, VCC1 pin, IN pin, FETG pin, GND1 pin, VCC2 pin, OUT pin, FB pin, and GND2 pin are shown as examples) as a means of establishing electrical connection with the outside of the device.

[0015] In the primary circuit system 1p of the electronic device 1, the VCC1 pin (primary side power supply terminal) is connected to the power supply line (= application terminal of the power supply voltage Vcc1) of the primary circuit system 1p. The IN pin (signal input terminal) is connected to a signal source (not shown). The FETG pin (gate connection terminal) is connected to the gate of the transistor N1. The GND1 pin (primary side ground terminal) and the source of the transistor N1 are both connected to the ground line (= application terminal of the ground voltage GND1) of the primary circuit system 1p.

[0016] Meanwhile, in the secondary circuit system 1s of the electronic device 1, the VCC2 pin (secondary power supply terminal) and the first end of resistor R1 are all connected to the power supply line of the secondary circuit system 1s (= the end to which the power supply voltage Vcc2 is applied). The OUT pin (signal output terminal) is connected to the gate of transistor Q1. The FB pin (feedback input terminal) is connected to the second end of resistor R1 and the first end of resistor R2. The GND2 pin (secondary ground terminal), the emitter of transistor Q1, and the second end of resistor R2 are all connected to the ground line of the secondary circuit system 1s (= the end to which the ground voltage GND2 is applied).

[0017] The flyback transformer 200, together with the transistor N1, the diode D1, and the capacitor C1, forms a flyback power supply (a type of isolated power supply that generates a power supply voltage Vcc2 for the secondary circuit system 1s from a power supply voltage Vcc1 for the primary circuit system 1p). The flyback transformer 200 includes a primary winding 200p and a secondary winding 200s that are magnetically coupled to each other while insulating the primary circuit system 1p from the secondary circuit system 1s.

[0018] A first terminal of the primary winding 200p is connected to the power supply line (= the terminal to which the power supply voltage Vcc1 is applied) of the primary circuit system 1p. A second terminal of the primary winding 200p is connected to the drain of the transistor N1. A first terminal of the secondary winding 200s is connected to the anode of the diode D1. The cathode of the diode D1 and a first terminal of the capacitor C1 are both connected to the power supply line (= the terminal to which the power supply voltage Vcc2 is applied) of the secondary circuit system 1s. A second terminal of the secondary winding 200s and a second terminal of the capacitor C1 are both connected to the ground line (= the terminal to which the ground voltage GND2 is applied) of the secondary circuit system 1s.

[0019] The signal transmission device 100 can be widely applied to general applications (such as motor drivers or DC / DC converters that handle high voltages) that require signal transmission between the primary circuit system 1p and the secondary circuit system 1s while isolating them from each other.

[0020] <Signal transmission device> Continuing with reference to Fig. 1, the internal configuration of the signal transmission device 100 will be described. The signal transmission device 100 of this configuration example has a controller chip 110 (corresponding to the first chip), a driver chip 120 (corresponding to the second chip), and a transformer chip 130 (corresponding to the third chip).

[0021] The controller chip 110 is a semiconductor chip that integrates circuit elements of a primary circuit system 1p that operates upon receiving a supply of power supply voltage Vcc1 (for example, a maximum of 7V relative to GND1). The driver chip 120 is a semiconductor chip that integrates circuit elements of a secondary circuit system 1s that operates upon receiving a supply of power supply voltage Vcc2 (for example, a maximum of 30V relative to GND2). The transformer chip 130 is a semiconductor chip that integrates a transformer for transmitting signals in both directions while insulating the controller chip 110 and the driver chip 120 from each other.

[0022] In this way, the signal transmission device 100 of this configuration example has an independent transformer chip 130 equipped with only a transformer, in addition to the controller chip 110 and driver chip 120, and these three chips are sealed in a single package.

[0023] With this configuration, the controller chip 110 and the driver chip 120 can both be formed using a general low to medium voltage withstand process (withstand voltage of several volts to several tens of volts), eliminating the need to use a dedicated high voltage withstand process (withstand voltage of several kV), thereby enabling reduction in manufacturing costs.

[0024] Furthermore, the controller chip 110 and the driver chip 120 can both be manufactured using existing processes with a proven track record, eliminating the need for new reliability testing, which contributes to shortening development time and reducing development costs.

[0025] Furthermore, even when an insulating element other than a transformer (e.g., a photocoupler) is used, it can be easily accommodated by simply replacing the transformer chip 130, which eliminates the need to redevelop the controller chip 110 and driver chip 120, thereby contributing to shortening the development period and reducing development costs.

[0026] Next, focusing on the main functional blocks, the signal transmission device 100 includes an isolated signal transmission circuit 10 and an isolated power supply control circuit 20.

[0027] The isolated signal transmission circuit 10 transmits a pulse signal from the primary circuit system 1p to the secondary circuit system 1s while isolating the primary circuit system 1p from the secondary circuit system 1s via an isolation element ISO1 (such as a transformer) integrated on a transformer chip 130. Referring to the figure, the isolated signal transmission circuit 10 transmits an input pulse signal S1 input to an IN pin of the primary circuit system 1p as an output pulse signal S2 output from an OUT pin of the secondary circuit system 1s.

[0028] The isolated power supply control circuit 20 is the main controller of the flyback power supply described above, and transmits the output feedback signal of the flyback power supply from the secondary circuit system 1s to the primary circuit system 1p while insulating the primary circuit system 1p from the secondary circuit system 1s via an isolation element ISO2 (such as a transformer) integrated on the transformer chip 130. Referring to this diagram, the isolated power supply control circuit 20 generates a gate drive signal S4 that is output from the FETG pin in response to an output feedback signal S3 (= a divided voltage of the power supply voltage Vcc2) that is input to the FB pin.

[0029] In this way, the signal transmission device 100 originally includes a transformer chip 130 that integrates an isolation element ISO1 used for signal transmission from the primary circuit system 1p to the secondary circuit system 1s. Therefore, by additionally integrating an isolation element ISO2 for controlling the isolated power supply into the transformer chip 130, it becomes possible to transmit the output feedback signal S3 of the flyback power supply from the secondary circuit system 1s to the primary circuit system 1p inside the signal transmission device 100.

[0030] In other words, with the signal transmission device 100 of this configuration example (particularly the isolated power supply control circuit 20), it is possible to directly detect the power supply voltage Vcc2 (corresponding to the output voltage of the flyback power supply) of the secondary circuit system 1s and transmit the detection result to the primary circuit system 1p of the flyback power supply. Therefore, unlike the conventional method that uses the auxiliary winding of the flyback transformer 200, it is possible to improve the output accuracy of the flyback power supply without being affected by load fluctuations, etc.

[0031] Furthermore, since there is no need to provide an auxiliary winding in the flyback transformer 200, it is possible to reduce the size of the flyback transformer 200 (and thus the size of the electronic device 1).

[0032] The circuit elements of the isolated signal transmission circuit 10 and the isolated power supply control circuit 20 are distributed and integrated in a controller chip 110, a driver chip 120, and a transformer chip 130 (details will be described later).

[0033] <Isolated signal transmission circuit> 2 is a diagram showing an example of the configuration of the isolated signal transmission circuit 10. The isolated signal transmission circuit 10 of this example configuration includes a Schmitt buffer 11, a pulse transmitting unit 12, a pulse receiving unit 13, a driver 14, and transformers 15 and 16 (corresponding to the aforementioned isolation element ISO1).

[0034] The Schmitt buffer 11 is an example of a waveform shaping means, and is connected between the IN pin and the pulse transmitting unit 12 .

[0035] The pulse transmitting unit 12 pulse-drives either one of the transmission pulse signals S1a and S1b in accordance with the logic level of the input pulse signal S1 input from the IN pin via the Schmitt buffer 11. For example, when notifying that the input pulse signal S1 is at a high level, the pulse transmitting unit 12 pulse-drives (outputs a single or multiple transmission pulses) the transmission pulse signal S1a to be applied to the primary winding 15p of the transformer 15, and when notifying that the input pulse signal S1 is at a low level, the pulse transmitting unit 12 pulse-drives the transmission pulse signal S1b to be applied to the primary winding 16p of the transformer 16.

[0036] The Schmitt buffer 11 and the pulse transmitting unit 12 are both integrated into the controller chip 110 of the primary circuit system 1p (Vcc1-GND1 system).

[0037] The pulse receiving unit 13 generates a receiving pulse signal S2c in response to the receiving pulse signals S2a and S2b input from the transformers 15 and 16, respectively. For example, when the pulse receiving unit 13 detects an induced pulse of the receiving pulse signal S2a appearing in the secondary winding 15s of the transformer 15 in response to the pulse drive of the transmitting pulse signal S1a, the pulse receiving unit 13 causes the receiving pulse signal S2c to fall to a low level. On the other hand, when the pulse receiving unit 13 detects an induced pulse of the receiving pulse signal S2b appearing in the secondary winding 16s of the transformer 16 in response to the pulse drive of the transmitting pulse signal S1b, the pulse receiving unit 13 causes the receiving pulse signal S2c to rise to a high level.

[0038] The driver 14 generates an output pulse signal S2 (corresponding to the gate signal of the transistor Q1) in response to the received pulse signal S2c input from the pulse receiving unit 13. For example, if an inverter is used as the driver 14, the output pulse signal S2 will be at a high level when the received pulse signal S2c is at a low level, and the output pulse signal S2 will be at a low level when the received pulse signal S2c is at a high level. In other words, the logical level of the output pulse signal S2 switches in response to the logical level of the input pulse signal S1.

[0039] The pulse receiving unit 13 and the driver 14 are both integrated into a driver chip 120 of the secondary circuit system 1s (Vcc2-GND2 system).

[0040] The transformer 15 outputs a received pulse signal S2a from a secondary winding 15s in response to a transmitted pulse signal S1a input to a primary winding 15p, while the transformer 16 outputs a received pulse signal S2b from a secondary winding 16s in response to a transmitted pulse signal S1b input to a primary winding 16p.

[0041] The above-mentioned transformers 15 and 16 are both integrated into the transformer chip 130. The transformer chip 130 uses the transformers 15 and 16 to insulate the controller chip 110 from the driver chip 120, and outputs the transmission pulse signals S1a and S1b input from the pulse transmitting unit 12 to the pulse receiving unit 13 as reception pulse signals S2a and S2b, respectively.

[0042] In this way, due to the characteristics of the spiral coil used for insulated communication, the input pulse signal S1 is separated into two transmission pulse signals S1a and S1b (corresponding to the rise signal and fall signal), and then transmitted from the primary circuit system 1p to the secondary circuit system 1s via two systems of transformers 15 and 16.

[0043] 3 is a diagram showing an example of an isolated signal transmission operation by the isolated signal transmission circuit 10, depicting, from top to bottom, an input pulse signal S1, transmission pulse signals S1a and S1b, reception pulse signals S2a to S2c, and an output pulse signal S2. For ease of explanation, the diagram does not depict signal delays.

[0044] The pulse transmitter 12 pulses the transmission pulse signal S1a at the rising edge of the input pulse signal S1 at time t1, and pulses the transmission pulse signal S1b at the falling edge of the input pulse signal S1 at time t2. The pulse receiver 13 detects an induced pulse in the reception pulse signal S2a generated by the pulse driving of the transmission pulse signal S1a and causes the reception pulse signal S2c to fall to a low level, while detecting an induced pulse in the reception pulse signal S2b generated by the pulse driving of the transmission pulse signal S1b and causes the reception pulse signal S2c to rise to a high level. As a result, when the input pulse signal S1 rises to a high level, the output pulse signal S2 also rises to a high level. Conversely, when the input pulse signal S1 falls to a low level, the output pulse signal S2 also falls to a low level.

[0045] <Insulated power supply control circuit> 4 is a diagram showing an example of the configuration of the isolated power supply control circuit 20. The isolated power supply control circuit 20 of this example configuration includes a charge pump 21, an oscillator 22, an adder 23, a comparator 24, an RS flip-flop 25, an overcurrent detection unit 26, a low input voltage detection unit 27, a comparator 28, a low input voltage detection unit 29, an output abnormality detection unit 2A, an OR gate 2B, and transformers 2C and 2D.

[0046] Of the above components, the charge pump 21, oscillator 22, adder 23, comparator 24, RS flip-flop 25, overcurrent detector 26, and low input voltage detector 27 are all integrated into the controller chip 110 of the primary circuit system 1p (Vcc1-GND1 system). On the other hand, the comparator 28, low input voltage detector 29, output abnormality detector 2A, and OR gate 2B are all integrated into the driver chip 120 of the secondary circuit system 1s (Vcc2-GND2 system). Furthermore, the transformers 2C and 2D are both integrated into the transformer chip 130.

[0047] Furthermore, this diagram clearly shows the COMP pin (phase compensation terminal) and FETS pin (current detection terminal) as external terminals of the signal transmission device 100, and also clearly shows capacitors C2 and C3 and resistors R3 and R4 as discrete components externally attached to these external terminals. In terms of connections, the COMP pin is connected to the first terminals of the resistor R3 and the capacitor C3. The second terminal of the resistor R3 is connected to the first terminal of the capacitor C2. The second terminals of the capacitors C2 and C3 are both connected to the ground line of the primary circuit system 1p (i.e., the terminal to which the ground voltage GND1 is applied). The FETS pin is connected to the source of the transistor N1 and the first terminal of the resistor R4. The second terminal of the resistor R4 is connected to the ground line of the primary circuit system 1p.

[0048] The charge pump 21 generates an analog signal S21 by charging and discharging capacitors C2 and C3 connected to the COMP pin in response to an output feedback pulse signal S2C input from the transformer 2C. For example, the charge pump 21 generates a charging current Ic when the output feedback pulse signal S2C is at a high level, and generates a discharging current Id when the output feedback pulse signal S2C is at a low level. Note that it is desirable to adjust the current ratio of the charging current Ic and the discharging current Id to 1:1 by trimming or the like.

[0049] The oscillator 22 generates a rectangular wave set signal S22a and a sawtooth wave slope signal S22b at a predetermined switching frequency (for example, 100 kHz). The oscillator 22 also has a function of generating a pulse of a maximum duty signal S22c when a predetermined time has elapsed since the generation of a pulse of the set signal S22a.

[0050] The adder 23 adds the slope signal S22b input from the oscillator 22 and the current detection signal Vcs input from the FETS pin to generate an added slope signal S23 (=S22b+Vcs).

[0051] Comparator 24 compares the analog signal S21 input to the non-inverting input terminal (+) with the added slope signal S23 input to the inverting input terminal (-) to generate a reset signal S24. The reset signal S24 becomes high level when S21 > S23, and becomes low level when S21 < S23. Note that a slope signal S22b may be input to the comparator 24 instead of the added slope signal S23.

[0052] The RS flip-flop 25 basically switches the logic level of the output signal S25 output from the output terminal (Q) according to the set signal S22a input to the set terminal (S) and the reset signal S24 input to the reset terminal (R). For example, the RS flip-flop 25 sets the output signal S25 to high level when the set signal S22a rises to high level, and resets the output signal S25 to low level when the reset signal S24 rises to high level. Note that the output signal S25 is output to the FETG pin as the gate drive signal S4 of the transistor N1 (corresponding to the output transistor of the flyback power supply). The transistor N1 turns on when the gate drive signal S4 is high level, and turns off when the gate drive signal S4 is low level.

[0053] In addition to the above reset signal S24, an overcurrent detection signal S26, a low input detection signal S27, and a secondary side abnormality detection signal S2D are input to the reset terminal (R) of the RS flip-flop 25. When any of the detection signals rises to high level, the output signal S25 (and thus the gate drive signal S4) is reset to low level. That is, the insulation power supply control circuit 20 of this configuration example has a function of forcibly stopping the flyback power supply when an abnormality of the signal transmission device 100 is detected.

[0054] Furthermore, the maximum duty signal S22c is input to the reset terminal (R) of the RS flip-flop 25, and when the maximum duty signal S22c rises to a high level, the output signal S25 (and hence the gate drive signal S4) is reset to a low level. In other words, the isolated power supply control circuit 20 of this configuration example also has a function of setting an upper limit on the output duty of the flyback power supply.

[0055] The overcurrent detection unit 26 monitors the current detection signal Vcs input from the FETS pin and generates the overcurrent detection signal S26. The overcurrent detection signal S26 becomes high level (logical level when an overcurrent is detected) when the current detection signal Vcs is higher than a predetermined overcurrent detection threshold. The overcurrent detection unit 26 also receives a soft-start voltage Vss, which gradually increases when the signal transmission device 100 is started up. When the soft-start voltage Vss is lower than the overcurrent detection threshold, the current detection signal Vcs is compared with the soft-start voltage Vss. As a result, when the signal transmission device 100 is started up, the primary current flowing through the transistor N1 gradually rises.

[0056] The low input voltage detector 27 monitors the power supply voltage Vcc1 of the primary circuit system 1p and generates a low input voltage detection signal S27. The low input voltage detection signal S27 goes high when the power supply voltage Vcc1 is lower than a UVLO (under voltage lock out) release voltage.

[0057] The comparator 28 generates an output feedback pulse signal S28 by comparing the triangular wave voltage Vtri input to its non-inverting input terminal (+) with the output feedback signal S3 (corresponding to the divided voltage of the power supply voltage Vcc2) input to its inverting input terminal (-) from the FB pin. The oscillation frequency of the triangular wave voltage Vtri may be set to an appropriate value (e.g., 200 kHz) depending on the frequency characteristics of the transformer 2C connected downstream of the comparator 28.

[0058] The low input voltage detector 29 monitors the power supply voltage Vcc2 of the secondary circuit system 1s and generates a low input voltage detection signal S29. The low input voltage detection signal S29 goes high when the power supply voltage Vcc2 is lower than the UVLO release voltage.

[0059] The output abnormality detection unit 2A monitors the output feedback signal S3 and generates the output abnormality detection signal S2A. The output abnormality detection signal S2A goes high when the output feedback signal S3 is abnormal (for example, when the output of the flyback power supply is open or shorted).

[0060] The OR gate 2B generates a secondary-side abnormality detection signal S2B by performing a logical OR operation on the low input voltage detection signal S29 and the output abnormality detection signal S2A. The secondary-side abnormality detection signal S2B is at a high level when at least one of the low input voltage detection signal S29 and the output abnormality detection signal S2A is at a high level, and is at a low level when both the low input voltage detection signal S29 and the output abnormality detection signal S2A are at a low level.

[0061] The transformer 2C provides insulation between the controller chip 110 and the driver chip 120, and outputs the output feedback pulse signal S28 of the secondary circuit system 1s input from the comparator 28 as the output feedback pulse signal S2C of the primary circuit system 1p to the charge pump 21. Note that in this figure, for convenience of illustration, the transformer 2C is depicted as receiving a signal input directly from the comparator 28, but in reality, a transmission pulse generating unit (a circuit unit similar to the pulse transmitting unit 12 described above) not shown is provided in the stage preceding the transformer 2C, and the rising edge and falling edge of the output feedback pulse signal S28 are transmitted using a pair of transformers.

[0062] The transformer 2D provides insulation between the controller chip 110 and the driver chip 120, and outputs the secondary-side abnormality detection signal S2B of the secondary circuit system 1s input from the OR gate 2B as the secondary-side abnormality detection signal S2D ​​of the primary circuit system 1p to the reset terminal (R) of the RS flip-flop 25. Note that in this figure, for convenience of illustration, the transformer 2D is depicted as receiving a signal input directly from the OR gate 2B, but in reality, a transmission pulse generation unit (a circuit unit similar to the aforementioned pulse transmission unit 12) not shown is provided in the stage preceding the transformer 2D, and the rising edge and falling edge of the secondary-side abnormality detection signal S2B are transmitted using a pair of transformers.

[0063] FIG. 5 is a diagram showing a first example of output feedback control by the isolated power supply control circuit 20 (when S3>VM), and depicts, from top to bottom, the output feedback signal S3 (solid line), the triangular wave voltage Vtri (dashed line), the output feedback pulse signal S28, the analog signal S21 (solid line), the additive slope signal S23 (dashed line), the reset signal S24, the set signal S22a, and the gate drive signal S4.

[0064] On the secondary side of the isolated power supply control circuit 20, an output feedback pulse signal S28 is generated by comparing the output feedback signal S3 externally input to the FB pin with the triangular wave voltage Vtri generated inside the signal transmission device 100. The output feedback pulse signal S28 has a lower duty as the output feedback signal S3 (and therefore the power supply voltage Vcc2) is higher, and a higher duty as the output feedback signal S3 is lower.

[0065] In this diagram, the output feedback signal S3 is higher than the middle value VM (=(VH+VL) / 2) of the triangular wave voltage Vtri, which periodically fluctuates between a peak value VH (e.g., 2 V) and a bottom value VL (e.g., 1 V), so the duty of the output feedback pulse signal S28 is lower than 50%. This state corresponds to a state in which the power supply voltage Vcc2 is higher than the target value.

[0066] The output feedback pulse signal S28 is transmitted from the secondary circuit system 1s to the primary circuit system 1p via the transformer 2C. That is, the isolated power supply control circuit 20 converts the output feedback signal S3, which corresponds to the power supply voltage Vcc2, into the output feedback pulse signal S28 and transmits it to the primary circuit system 1p.

[0067] Meanwhile, on the primary side of the isolated power supply control circuit 20, an analog signal S21 is generated in accordance with the duty of the output feedback pulse signal S28 (more precisely, the output feedback pulse signal S2C transmitted via the transformer 2C). In this diagram, the duty of the output feedback pulse signal S28 is below 50%, so the analog signal S21 shows a downward trend.

[0068] Furthermore, the analog signal S21 and the added slope signal S23 are compared to generate the reset signal S24. At this time, the lower the analog signal S21, the earlier the timing of intersection with the added slope signal S23 (=the timing of pulse generation of the reset signal S24).

[0069] The gate drive signal S4 for transistor N1 is generated based on the set signal S22a and the reset signal S24. As described above, the gate drive signal S4 is set to a high level when the set signal S22a rises to a high level, and is reset to a low level when the reset signal S24 rises to a high level. Therefore, the earlier the pulse generation timing of the reset signal S24, the earlier transistor N1 is turned off.

[0070] In this way, when the power supply voltage Vcc2 is higher than the target value, the output duty of the flyback power supply is reduced to lower the power supply voltage Vcc2, and output feedback is applied so that the power supply voltage Vcc2 matches the target value.

[0071] FIG. 6 is a diagram showing a second example of output feedback control by the insulation power control circuit 20 (when S3 <VM). Similar to FIG. 5 above, in order from the top, the output feedback signal S3 (solid line) and the triangular wave voltage Vtri (dashed line), the output feedback pulse signal S28, the analog signal S21 (solid line), and the addition slope signal S23 (dashed line), the reset signal S24, the set signal S22a, and the gate drive signal S4 are depicted.

[0072] The basic operation of the output feedback control is the same as that of FIG. 5 above. However, in this figure, since the output feedback signal S3 is lower than the middle value VM of the triangular wave voltage Vtri, the duty of the output feedback pulse signal S28 is higher than 50%. Such a state corresponds to a state where the power supply voltage Vcc2 is lower than the target value.

[0073] In this case, the analog signal S21 generated on the primary side of the insulation power control circuit 20 tends to increase. Note that the higher the analog signal S21, the later the crossing timing with the addition slope signal S23 (= the pulse generation timing of the reset signal S24), so the transistor N1 is turned on for a longer time.

[0074] In this way, when the power supply voltage Vcc2 is lower than the target value, by increasing the output duty of the flyback power supply, the power supply voltage Vcc2 is pulled up, so that output feedback is applied so that the power supply voltage Vcc2 matches the target value.

[0075] Note that when the output feedback signal S3 matches the middle value of the triangular wave voltage Vtri and the duty of the output feedback pulse signal S28 is maintained near 50%, the generation times of the charging current Ic and the discharging current Id by the charge pump 21 are equal, so the analog signal S21 is stabilized. Such a state corresponds to a state where the power supply voltage Vcc2 is adjusted to the target value.

[0076] <Application to Vehicles> 7 is a diagram showing the appearance of a vehicle equipped with electronic devices. The vehicle X of this configuration example is equipped with various electronic devices X11 to X18 that operate by receiving power supply from a battery (not shown). Note that the installation positions of the electronic devices X11 to X18 in this figure may differ from the actual positions for convenience of illustration.

[0077] Vehicle X includes not only engine vehicles but also electric vehicles (battery electric vehicles [BEVs], hybrid electric vehicles [HEVs], plug-in hybrid electric vehicles [PHEVs / PHVs], or xEVs such as fuel cell electric vehicles / fuel cell vehicles [FCEVs / FCVs]).

[0078] The electronic device X11 is an electronic control unit that performs engine-related controls (such as injection control, electronic throttle control, idling control, oxygen sensor heater control, and auto-cruise control) or motor-related controls (such as torque control and power regeneration control).

[0079] The electronic device X12 is a lamp control unit that controls the turning on and off of HID (high intensity discharged lamp) and DRL (daytime running lamp).

[0080] The electronic device X13 is a transmission control unit that controls transmission-related functions.

[0081] The electronic device X14 is a braking unit that performs control related to the movement of the vehicle X (ABS (anti-lock brake system) control, EPS (electric power steering) control, electronic suspension control, etc.).

[0082] The electronic device X15 is a security control unit that controls the operation of door locks, burglar alarms, and the like.

[0083] The electronic device X16 is an electronic device that is installed in the vehicle X at the time of shipment from the factory as a standard equipment or a manufacturer option, such as a wiper, an electric door mirror, a power window, a damper (shock absorber), an electric sunroof, and an electric seat.

[0084] The electronic device X17 is an electronic device that is optionally installed in the vehicle X as a user option, such as an in-vehicle A / V (audio / visual) device, a car navigation system, and an ETC (electronic toll collection system).

[0085] The electronic device X18 is an electronic device equipped with a high-voltage motor, such as an in-vehicle blower, oil pump, water pump, or battery cooling fan.

[0086] The electronic devices X11 to X18 can be understood as specific examples of the previously described electronic device 1. That is, the signal transmission device 100 described above can be incorporated into any of the electronic devices X11 to X18.

[0087] <Summary> The following will provide a general overview of the various embodiments described above.

[0088] For example, the signal transmission device disclosed in this specification has a configuration (first configuration) that includes an isolated signal transmission circuit configured to transmit a pulse signal from a primary circuit system to a secondary circuit system via a first insulating element, and an isolated power supply control circuit that is a control entity of an isolated power supply that generates a second power supply voltage for the secondary circuit system from a first power supply voltage for the primary circuit system, and is configured to transmit an output feedback signal of the isolated power supply from the secondary circuit system to the primary circuit system via a second insulating element.

[0089] In addition, in the signal transmission device having the above-mentioned first configuration, the isolated power supply control circuit may be configured (second configuration) to convert the output feedback signal corresponding to the second power supply voltage into an output feedback pulse signal and transmit it to the primary circuit system.

[0090] Furthermore, in the signal transmission device having the second configuration described above, the isolated power supply control circuit may have a configuration (third configuration) including a comparator configured to generate the output feedback pulse signal by comparing the output feedback signal with a triangular wave voltage in the secondary circuit system.

[0091] Furthermore, in the signal transmission device having the second or third configuration, the isolated power supply control circuit may be configured (fourth configuration) to generate an analog signal corresponding to the duty of the output feedback pulse signal in the primary circuit system and control the output duty of the isolated power supply by comparing the analog signal with a slope signal.

[0092] Furthermore, in the signal transmission device having the above-described fourth configuration, the isolated power supply control circuit may have a configuration (fifth configuration) including a charge pump configured to generate the analog signal by charging and discharging a capacitor in the primary circuit system in response to the output feedback pulse signal.

[0093] Furthermore, in a signal transmission device having any of the above first to fifth configurations, the isolated power supply control circuit may be configured (sixth configuration) to forcibly stop the isolated power supply when an abnormality is detected in the signal transmission device (for example, when an abnormality is detected in any of the first power supply voltage, the second power supply voltage, and the output feedback signal).

[0094] Furthermore, a signal transmission device having any of the first to sixth configurations above may have a configuration (seventh configuration) in which a first chip on which circuit elements of the primary circuit system are integrated, a second chip on which circuit elements of the secondary circuit system are integrated, and a third chip on which the first isolation element and the second isolation element are integrated are sealed in a single package.

[0095] Furthermore, in a signal transmission device having any of the above first to seventh configurations, the isolated signal transmission circuit may have a configuration (eighth configuration) including: a first transformer and a second transformer corresponding to the first isolation element; a pulse transmitting unit configured to pulse-drive a first transmission pulse signal to be applied to the primary winding of the first transformer when notifying that the input pulse signal is at a first logic level, and to pulse-drive a second transmission pulse signal to be applied to the primary winding of the second transformer when notifying that the input pulse signal is at a second logic level; a pulse receiving unit configured to set the received pulse signal to the first logic level when an induced pulse of a first received pulse signal appearing in the secondary winding of the first transformer in response to the pulse-driving of the first transmission pulse signal is detected, and to set the received pulse signal to the second logic level when an induced pulse of a second received pulse signal appearing in the secondary winding of the second transformer in response to the pulse-driving of the second transmission pulse signal is detected; and a driver configured to generate an output pulse signal according to the received pulse signal.

[0096] Furthermore, for example, the electronic device disclosed in this specification has a configuration (ninth configuration) that includes a signal transmission device having any one of the first to eighth configurations above.

[0097] Furthermore, for example, the vehicle disclosed in this specification has a configuration (tenth configuration) including the electronic device having the ninth configuration described above.

[0098] <Other variations> In addition to the above-described embodiments, the various technical features disclosed in this specification can be modified in various ways without departing from the spirit of the technical creation. In other words, the above-described embodiments should be considered to be illustrative and not restrictive in all respects, and the technical scope of the present invention should not be limited to the above-described embodiments, but should be understood to include all modifications that fall within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0099] 1 Electronic equipment 1p primary circuit system 1s secondary circuit system 10. Isolated signal transmission circuit 11 Schmitt Buffer 12 Pulse transmitter 13 Pulse receiving unit 14 Drivers 15, 16 Transformer 15p, 16p primary winding 15s, 16s secondary winding 20. Isolated power supply control circuit 21 Charge Pump 22 oscillators 23 Adder 24 Comparator 25 RS Flip-Flop 26 Overcurrent detection section 27 Low input detection unit 28 Comparator 29 Low input detection section 2A output abnormality detection section 2B OR gate 2C, 2D transformers 100 Signal transmission device (isolated gate driver IC) 110 Controller Chip 120 driver chip 130 Transformer Chip 200 Flyback transformer 200p primary winding 200s Secondary Winding C1, C2, C3 capacitors D1 Diode N1 N-channel MOS field effect transistor Q1 npn-type insulated gate bipolar transistor R1, R2, R3, R4 resistance TR1, TR2 transformers X vehicle X11~X18 Electronic equipment

Claims

1. a first external terminal configured to receive an external input of an input pulse signal in the primary circuit system; a second external terminal to which a first control electrode of a first transistor in the secondary circuit system is externally connected and configured to output an output pulse signal to the first control electrode; an isolated signal transmission circuit configured to generate an internal pulse signal in response to the input pulse signal externally input via the first external terminal, transmit the internal pulse signal from the primary circuit system to a secondary circuit system via a first insulating element, generate an output pulse signal in response to the internal pulse signal transmitted to the secondary circuit system, and externally output the output pulse signal to the first control electrode of the first transistor via the second external terminal, thereby controlling on / off of the first transistor; an isolated power supply control circuit which is a control entity of an isolated power supply that generates a second power supply voltage for the secondary circuit system from a first power supply voltage for the primary circuit system, and is configured to transmit an output feedback signal of the isolated power supply from the secondary circuit system to the primary circuit system via a second isolation element; a third external terminal configured to receive an external input of the first power supply voltage in the primary circuit system and to have a third insulating element of the isolated power supply externally connected thereto; a fourth external terminal configured to receive an external input of the second power supply voltage in the secondary circuit system; a fifth external terminal configured to receive an external input of the output feedback signal in the secondary circuit system; a sixth external terminal configured to externally connect a second control electrode of a second transistor connected to the third insulating element in the primary circuit system; A semiconductor device comprising:

2. The isolated signal transmission circuit comprises: a first transformer and a second transformer corresponding to the first insulating element; a pulse transmitting unit provided in the primary circuit system, operating upon receiving the first power supply voltage, configured to pulse-drive a first transmission pulse signal to be applied to a primary winding of the first transformer when notifying that the input pulse signal is at a first logic level, and to pulse-drive a second transmission pulse signal to be applied to a primary winding of the second transformer when notifying that the input pulse signal is at a second logic level; a pulse receiving unit provided in the secondary circuit system, which operates upon receiving the second power supply voltage, and which is configured to set a received pulse signal to a first logic level when an induced pulse of a first received pulse signal appearing in a secondary winding of the first transformer in response to pulse driving of the first transmitted pulse signal is detected, and to set the received pulse signal to a second logic level when an induced pulse of a second received pulse signal appearing in a secondary winding of the second transformer in response to pulse driving of the second transmitted pulse signal is detected; a driver provided in the secondary circuit system, which operates upon receiving the second power supply voltage and is configured to generate an output pulse signal in response to the received pulse signal; The semiconductor device according to claim 1 , comprising:

3. 3. The semiconductor device according to claim 1, wherein said isolated power supply control circuit converts said output feedback signal corresponding to said second power supply voltage into an output feedback pulse signal and transmits the output feedback pulse signal to said primary circuit system.

4. 4. The semiconductor device according to claim 3, wherein said isolated power supply control circuit includes a comparator configured to generate said output feedback pulse signal by comparing said output feedback signal with a triangular wave voltage in said secondary circuit system.

5. 5. The semiconductor device according to claim 3, wherein the isolated power supply control circuit generates an analog signal corresponding to a duty of the output feedback pulse signal in the primary circuit system, and controls the output duty of the isolated power supply by comparing the analog signal with a slope signal.

6. 6. The semiconductor device according to claim 5, wherein said isolated power supply control circuit includes a charge pump configured to generate said analog signal by charging and discharging a capacitor in said primary circuit system in response to said output feedback pulse signal.

7. 7. The semiconductor device according to claim 1, wherein said isolated power supply control circuit forcibly stops said isolated power supply when an abnormality in said signal transmission device is detected.

8. a first chip on which circuit elements of the primary circuit system are integrated; a second chip on which circuit elements of the secondary circuit system are integrated; a third chip on which the first isolation element and the second isolation element are integrated; 8. The semiconductor device according to claim 1, wherein the first and second electrodes are sealed in a single package.

9. A semiconductor device according to any one of claims 1 to 8, the first transistor configured such that the first control electrode is externally connected to the second external terminal of the semiconductor device; the second transistor configured such that the second control electrode is externally connected to the sixth external terminal of the semiconductor device; the third isolation element configured to be externally attached to the third external terminal of the semiconductor device to form the isolated power supply; An electronic device having:

10. A vehicle comprising the electronic device according to claim 9.

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