Starting circuit and chip

Abstract

The utility model relates to the technical field of electronic circuits, and discloses a starting circuit and a chip, the starting circuit comprises a first charging circuit, a first transistor and a first capacitor, a gate-drain capacitor is arranged between the gate electrode and the drain electrode of the first transistor; a first end of the first charging circuit is connected with a power supply and a source electrode of the first transistor, a second end of the first charging circuit is connected with a first end of the first capacitor and a grid electrode of the first transistor, a second end of the first capacitor is connected with a drain electrode of the first transistor, and a first end of the first capacitor is connected with the grid electrode of the first transistor. The first charging circuit charges the first capacitor and the gate-drain capacitor based on the output voltage of the power supply; when the gate-source voltage of the first transistor reaches a first threshold value, the first capacitor and the gate-drain capacitor discharge. The starting current can be reduced based on the circuit.

Description

Technical Field

[0001] The utility model relates to the field of circuits, in particular to a starting circuit and a chip. Background Art

[0002] The KL30 line is a power line in the automotive electrical system, and is typically used to power electrical devices and systems in vehicles such as the vehicle.

[0003] However, when the starting current corresponding to the KL30 circuit is too large, it may damage the battery and cause other devices or systems to malfunction. Utility Model Content

[0004] The embodiment of the present application provides a startup circuit and a chip, which increases the Miller time and prolongs the startup time by adding capacitance between the gate and drain of a metal oxide semiconductor field effect transistor, thereby reducing the startup current.

[0005] In a first aspect, the present application provides a startup circuit, which includes a first charging circuit, a first transistor, and a first capacitor, wherein a gate-drain capacitor is provided between the gate and the drain of the first transistor; a first end of the first charging circuit is connected to a power supply and the source of the first transistor, a second end of the first charging circuit is connected to the first end of the first capacitor and the gate of the first transistor, a second end of the first capacitor is connected to the drain of the first transistor, a first end of the first capacitor is connected to the gate of the first transistor, and the first charging circuit charges the first capacitor and the gate-drain capacitor based on the output voltage of the power supply; when the gate-source voltage of the first transistor reaches a first threshold, the first capacitor and the gate-drain capacitor are discharged.

[0006] In some optional examples of the first aspect, the startup circuit also includes: a first discharge circuit, a first voltage stabilization protection circuit, a first output matching circuit, and a first filter circuit; the first end of the first discharge circuit is connected to the second end of the first capacitor and the drain of the first transistor; the first end of the first voltage stabilization protection circuit is connected to the power supply, and the second end of the first voltage stabilization protection circuit is connected to the first charging circuit; the first output matching circuit and the first filter circuit are connected in sequence.

[0007] In some optional instances of the first aspect, when the gate-source voltage of the first transistor reaches a first threshold, the first capacitor and the gate-drain capacitor are discharged based on the first discharge circuit; wherein, the first discharge time of the first discharge circuit for the first capacitor and the gate-drain capacitor is greater than the second discharge time of the first discharge circuit for discharging the gate-drain capacitor.

[0008] In some optional examples of the first aspect, the first charging circuit includes at least one charging resistor and a first diode;

[0009] At least one charging resistor is connected in parallel with the first diode.

[0010] In some optional examples of the first aspect, the first transistor is a P-type MOSFET tube

[0011] In some optional examples of the first aspect, the first discharge circuit is composed of at least one discharge resistor.

[0012] In some optional examples of the first aspect, the first voltage stabilizing protection circuit includes at least one voltage stabilizing resistor and at least one voltage stabilizing diode; the at least one voltage stabilizing resistor and the at least one voltage stabilizing diode are connected in parallel.

[0013] In some optional examples of the first aspect, the first output matching circuit includes at least one polar capacitor and at least one non-polar capacitor; the polar capacitor and the non-polar capacitor are grounded and connected in parallel.

[0014] In some optional examples of the first aspect, the first filter circuit is composed of a first filter capacitor, a second filter capacitor and a first filter inductor; the first filter capacitor and the second filter capacitor are connected in parallel and then grounded, and the first filter inductor and the second filter capacitor are connected in series and then grounded.

[0015] In a second aspect, the present application provides a chip, the chip comprising the charging circuit as mentioned in the first aspect above.

[0016] The beneficial effects of the present application are as follows: in the startup circuit, the drain and gate of the first transistor directly increase the external capacitance, which is equivalent to increasing the Miller capacitance of the corresponding first transistor. The discharge time of the corresponding Miller capacitance increases, that is, the Miller time increases. Therefore, the startup time increases and the startup current decreases. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1A According to some embodiments of the present application, a startup circuit 10 is shown;

[0018] Figure 1B According to some embodiments of the present application, a schematic diagram of voltage and current changes of a starting circuit 10 is shown;

[0019] Figure 2 According to some embodiments of the present application, a startup circuit 00 is shown;

[0020] Figure 3A According to some embodiments of the present application, a circuit schematic diagram of a startup circuit 00 is shown;

[0021] Figure 3B According to some embodiments of the present application, a schematic diagram of voltage and current changes of a starting electrical circuit 00 is shown.

[0022] Figure numerals: 10-starting circuit, 100-power supply, 101-capacitor, 102-voltage regulator, 103-MOSFET tube (i.e. metal oxide semiconductor field effect tube), 104-polarity capacitor, 105-capacitor, 106-capacitor, 107-capacitor, 108-inductor and 109-resistance, 111-first end of capacitor 101, 112-second end of capacitor 101, 121-first end of voltage regulator tube 102, 122-second end of voltage regulator tube 102, 131-MOSFET tube 10 3 - source (Source), 132 - gate (Gate) of MOSFET tube 103, 133 - drain (Drain) of MOSFET tube 103, 141 - first end of polarity capacitor 104, 142 - second end of polarity capacitor 104, 151 - first end of capacitor 105, 152 - second end of capacitor 105, 161 - first end of capacitor 106, 162 - second end of capacitor 106, 171 - first end of capacitor 107, 172 - second end of capacitor 107. 181-the first end of the inductor 108, 182-the second end of the inductor 108, 191-the first end of the resistor 109, 192-the first end of the resistor 109, 00-start-up circuit, 02-the first transistor, 03-the first capacitor, 04-the discharge circuit, 05-the output matching circuit, 06-the filter circuit, 01a-the first end of the charging circuit 01, 01b-the second end of the charging circuit 01, 02a-the source of the first transistor 02, 02b-the gate of the first transistor 02, 02c-the drain of the first transistor 02, 03a-the first end of the first capacitor 03, 03b-the second end of the first capacitor 03, 04a-the first end of the discharge circuit 04, 05a-the first end of the output matching circuit 05, 05b-the second end of the output matching circuit 05, 06a-the first end of the filter circuit 06, 200-the power supply, 201-the resistor, 202-the voltage regulator, 203-MOSFET tube (i.e. metal oxide semiconductor field effect transistor), 204-polar capacitor, 205-capacitor, 206-capacitor, 207-capacitor, 208-inductor, 209-resistor, 210-diode, 220-capacitor, 230-resistor, 231-source (Source) of MOSFET tube 203, 232-gate (Gate) of MOSFET tube 203, 233-drain (Drain), 211-first end of resistor 201, 112-second end of resistor 201, 221-first end of voltage regulator tube 202, 222-second end of voltage regulator tube 202, 2102-second end of diode 210, 2201-first end of capacitor 220, 2202-second end of capacitor 220, 2301-first end of resistor 230, 2302-second end of resistor 230, 291-first end of resistor 209, 292-second end of resistor 209. DETAILED DESCRIPTION

[0023] The starting circuits mentioned in some embodiments are introduced below.

[0024] Figure 1A According to some embodiments of the present application, a startup circuit 10 is shown. As shown in FIG.

[0025] Exemplarily, FIG1 shows a startup circuit 10, which includes a power supply 100, a capacitor 101, a voltage regulator 102, a MOSFET 103 (i.e., a metal oxide semiconductor field effect transistor), a polar capacitor 104, a capacitor 105, a capacitor 106, a capacitor 107, an inductor 108, and a resistor 109. The MOSFET 103 includes a source 131, a gate 132, and a drain 133.

[0026] Based on the startup circuit 10 shown in FIG1 , capacitor 101 and voltage regulator tube 102 form a voltage stabilization protection circuit to ensure that the voltage of the KL30 power supply line is stable during the startup process and to prevent the MOSFET tube 103 from being damaged by breakdown due to excessive instantaneous voltage. Polar capacitor 104 and capacitor 105 form an output matching circuit, the purpose of which is to offset the impedance of the switching power supply in the components and reduce power consumption. Capacitor 106, capacitor 107 and inductor 108 form a filter circuit, which is used for signal filtering and processing, reducing conducted interference, and facilitating subsequent electromagnetic compatibility (EMC) testing of the circuit.

[0027] In some examples, in the startup circuit 10, the first end 111 of the capacitor 101, the first end 121 of the voltage regulator tube 102, and the source 131 of the MOSFET tube 103 are connected to the power supply 100. The second end 112 of the capacitor 101 is connected to the second end 122 of the voltage regulator tube 102 to form a voltage stabilization protection circuit, and then connected to the gate 132 of the MOSFET tube 103. The drain 133 of the MOSFET tube 103 is connected to the first end 141 of the polar capacitor 104, the first end 151 of the capacitor 105, the first end 161 of the capacitor 106, and the first end 171 of the capacitor 107. The second end 142 of the polar capacitor 104, the second end 152 of the capacitor 105, the second end 162 of the capacitor 106, and the second end 172 of the capacitor 107 are all grounded. The first end 181 of the inductor 108 is also connected to the first end 161 of the capacitor 106, and the second end 182 of the inductor 108 is connected to the first end 171 of the capacitor 107. The first end 191 of the resistor 109 is connected to the gate 132 of the MOSFET tube 103, and the first end 192 of the resistor 109 is connected to other device circuit components (not shown in the figure).

[0028] Because the on-time of the MOSFET tube 103 is extremely short, when the gate-source voltage Vgs reaches the starting voltage of the MOSFET tube 103, the voltage difference between the source (Source) 131 and the gate (Gate) 132 of the MOSFET tube 103 rises from 0V to the power supply voltage. At this time, the load capacitor will be rapidly charged, so the starting current is very large.

[0029] In some embodiments, Figure 1B FIG. 1 shows a schematic diagram of voltage and current changes of a starting circuit 10. Figure 1B In the graph, the b-coordinate graph is the starting current value changing with time; the horizontal axis is time, for example, ms, and the vertical axis is current, in A. The a-coordinate graph is the gate-source voltage V gs A graph of changes over time, with the horizontal axis being time, e.g. ms, and the vertical axis being voltage, in V.

[0030] It can be understood that in the startup circuit 10, since the capacitance of the gate-drain capacitor Cgd is very small, the discharge time of the gate-drain capacitor Cgd (not shown in the figure) in the MOSFET tube 103, that is, the Miller platform time, is very short, and the corresponding drain voltage Vds drops rapidly. At this time, the drain current Id also changes greatly, reaching a higher peak value in a short time, for example Figure 1B The current value at point A in the b coordinate diagram.

[0031] When the starting current corresponding to the KL30 circuit is too large, it may damage the battery and cause other devices or systems to malfunction. For example, when the starting current is too large, it will cause the battery to output a large amount of current instantly, thereby increasing the load on the battery. If the battery cannot withstand this load, it may shorten the battery life or cause damage. For another example, a corresponding starting current that is too large may cause the KL30 starting circuit to overload, because the KL30 starting circuit cannot withstand such a large current, resulting in a short circuit, burning of the circuit, or other electrical failures. For another example, a corresponding starting current that is too large will cause the voltage on the KL30 power supply line to drop, because a certain voltage drop will be generated when the current passes through the line. If the voltage drop is too large, it may affect the normal operation of other devices and systems, such as sensors, control units, etc. These devices and systems may not work properly or produce incorrect outputs, resulting in failure of the entire vehicle system.

[0032] In order to solve the above problems, the embodiment of the present application provides a startup circuit 00, which is exemplarily: Figure 2 The figure shows a startup circuit 00 , which includes a charging circuit 01 , a first transistor 02 , a first capacitor 03 , a discharging circuit 04 , an output matching circuit 05 , and a filtering circuit 06 .

[0033] The first transistor 02 includes a source 02a, a gate 02b and a drain 02c.

[0034] It can be understood that in the startup circuit 00, the first end 01a of the charging circuit 01 is connected to the source 02a of the first transistor 02 and the power supply (not shown in the figure), and the second end 01b of the charging circuit 01 is connected to the second end 03b of the first capacitor 03 and the gate 02b of the first transistor 02. The first end 03a of the first capacitor 03 is connected to the drain 02c of the first transistor 02. The second end 03b of the first capacitor 03 is connected to the gate 02b of the first transistor 02. The first end 04a of the discharge circuit 04 is connected to the second end 03b of the first capacitor 03. The output matching circuit 05 and the filter circuit 06 are connected in sequence, that is, the first end 05a of the output matching circuit 05 is connected to the first end 03a of the first capacitor 03, and the first end 05a of the output matching circuit 05 is connected to the first end 06a of the filter circuit 06.

[0035] It can be understood that when the charging circuit 01 fully charges the first capacitor 03, the source (Source) 02a of the first transistor 02 and the gate (Gate) 02b of the first transistor 02 are both at high levels, and the voltage value is close to the power supply voltage. When the second end 04b of the discharge circuit 04 is connected to the load, the second end 04b of the discharge circuit 04 is at a low level, and the voltage value is close to zero; the first end 04a of the discharge circuit 04 is connected to the second end 03b of the first capacitor 03 and is at a high level. At this time, due to the voltage difference, the first capacitor 03 and the gate-drain capacitance Cgd of the first transistor 02 are slowly discharged through the discharge circuit 04, and the voltage of the gate (Gate) 02b of the first transistor 02 is also reduced. Therefore, a voltage difference is generated between the source (Source) 02a of the first transistor 02 and the gate (Gate) 02b of the first transistor 02. When the voltage difference, that is, the gate-source voltage Vgs, is greater than the starting voltage V TH When the first transistor 02 starts to conduct, it can be understood that the addition of the first capacitor 03 prolongs the Miller platform time of the first transistor 02. During this period, the drain voltage of the MOSFET tube 203 gradually rises to the power supply voltage. Therefore, the startup current reaches a relatively small peak value in a relatively long period of time.

[0036] The specific implementation process of the technical solution provided in the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0037] Figure 3A A circuit diagram of a startup circuit 00 in an embodiment of the present application is shown.

[0038] The startup circuit 200 includes a power supply 200, a resistor 201, a voltage regulator 202, a MOSFET 203 (i.e., a metal oxide semiconductor field effect transistor), a polar capacitor 204, a capacitor 205, a capacitor 206, a capacitor 207, an inductor 208, a resistor 209, a diode 210, a capacitor 220, and a resistor 230. The MOSFET 203 includes a source 231, a gate 232, and a drain 233.

[0039] In some examples, in the startup circuit 00, the first end 211 of the resistor 201, the first end 221 of the voltage regulator tube 202, and the source 231 of the MOSFET tube 203 are connected to the power supply 100. The second end 112 of the resistor 101 is connected to the second end 2102 of the diode 210 to form a charging circuit, and then connected to the second end 2202 of the capacitor 220. The drain 233 of the MOSFET tube 203 is connected to the first end 2201 of the capacitor 220. The second end 2202 of the capacitor 220 is connected to the gate 232 of the MOSFET tube 203. The resistor 230 and the resistor 209 are connected in sequence, that is, the first end 2301 of the resistor 230 is connected to the second end 2202 of the capacitor 220, and the second end 2302 of the resistor 230 is connected to the first end 291 of the resistor 209. The resistor 230 and the resistor 209 form a discharge circuit, which discharges slowly during discharge to increase the Miller time. The second end 292 of the resistor 209 is connected to other components (not shown in the figure). In other embodiments, the discharge circuit may be composed of one or more resistors, not limited to the resistor 230 and the resistor 209, and is not limited here.

[0040] Continue to refer Figure 3A The first end 241 of the polar capacitor 204, the first end 251 of the capacitor 205, the first end 261 of the capacitor 206, and the first end 271 of the capacitor 207 are connected to the drain 233 of the MOSFET tube 203. The second end 242 of the polar capacitor 204, the second end 252 of the capacitor 205, the second end 262 of the capacitor 206, and the second end 272 of the capacitor 207 are all grounded. The first end 281 of the inductor 208 is also connected to the first end 261 of the capacitor 206, and the second end 282 of the inductor 208 is connected to the first end 271 of the capacitor 207.

[0041] It can be understood that when the charging circuit composed of the resistor 101 and the diode 210 fully charges the capacitor 220, the source (Source) 231 of the MOSFET tube 203 and the gate (Gate) 232 of the MOSFET tube 203 are both high level, and the voltage value is close to the power supply voltage. When the discharge circuit composed of the resistor 230 and the resistor 209 is connected to the load, the second end 292 of the resistor 209 is at a low level, and the voltage value is close to zero; the first end 231 of the resistor 230 is connected to the second end 222 of the capacitor 220 at a high level. At this time, due to the voltage difference, the capacitor 220 and the gate-drain capacitance of the MOSFET tube 203 are slowly discharged through the discharge circuit, and the voltage of the gate (Gate) 232 of the MOSFET tube 203 is also reduced, so a voltage difference is generated between the source (Source) 231 of the MOSFET tube 203 and the gate (Gate) 232 of the MOSFET tube 203. When the voltage difference, that is, the gate-source voltage V gs Greater than the starting voltage V TH , the MOSFET tube 203 starts to conduct.

[0042] It can be understood that the first end 2201 and the second end 2202 of the capacitor 220 are respectively connected to the drain 233 of the MOSFET tube 203 and the gate 232 of the MOSFET tube 203. This is equivalent to increasing the Miller capacitor Cgd in the MOSFET tube 203, and also increasing the discharge time of the Miller capacitor, that is, the Miller time increases, the startup time is extended, and the startup current is reduced.

[0043] Continue to refer Figure 3A The polarized capacitor 204 and the capacitor 205 form an output matching circuit, the purpose of which is to offset the impedance of the switch and the power supply in the components and reduce power consumption. The capacitor 206, the capacitor 207 and the inductor 208 form a filter circuit, which is used to filter the output voltage and other signals, reduce the conducted interference, and facilitate the subsequent electromagnetic compatibility (EMC) test of the circuit.

[0044] In some embodiments, Figure 3B According to some embodiments of the present application, a schematic diagram of voltage and current changes of a startup circuit 00 is shown. Figure 3B In the figure, the c coordinate graph is the starting current variation graph with time; the horizontal axis is time, for example, ms, the vertical axis is current, the unit is A, and the d coordinate graph is the gate-source voltage V gs A graph of changes over time, with the horizontal axis being time, e.g. ms, and the vertical axis being voltage, in V.

[0045] Depend on Figure 3B and Figure 1B From T and T' in, we can see that Figure 3BThe corresponding Miller time T' increases significantly, and the starting current reaches a relatively small peak value within the relatively long Miller time T'.

[0046] This embodiment is a startup circuit implementation method corresponding to the above circuit embodiment, and this embodiment can be implemented in conjunction with the circuit implementation method. The relevant technical details mentioned in the circuit implementation method are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the circuit implementation method.

[0047] An embodiment of the present application provides a chip, which may include a startup circuit.

[0048] This embodiment is a chip implementation corresponding to the above circuit embodiment, and this embodiment can be implemented in conjunction with the startup circuit implementation. The relevant technical details mentioned in the circuit implementation are still valid in this embodiment, and in order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the circuit implementation.

[0049] It should be noted that, in the examples and description of the present utility model, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise one" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0050] Although the utility model has been disclosed as a preferred embodiment, the utility model is not limited thereto. Any changes and modifications made by any person skilled in the art without departing from the spirit and scope of the utility model should be included in the protection scope of the utility model, so the protection scope of the utility model should be based on the scope defined by the claims.

Claims

1. A starting circuit, characterized in that: The startup circuit comprises a first charging circuit, a first transistor, and a first capacitor, wherein a gate-drain capacitor is provided between the gate and the drain of the first transistor; A first end of the first charging circuit is connected to a power source and a source of the first transistor, a second end of the first charging circuit is connected to a first end of the first capacitor and a gate of the first transistor, a second end of the first capacitor is connected to a drain of the first transistor, and a first end of the first capacitor is connected to the gate of the first transistor; The first charging circuit charges the first capacitor and the gate-drain capacitor based on the output voltage of the power supply; When the gate-source voltage of the first transistor reaches a first threshold, the first capacitor and the gate-drain capacitor are discharged.

2. The circuit according to claim 1, characterized in that The startup circuit further includes: a first discharge circuit, a first voltage stabilization protection circuit, a first output matching circuit, and a first filtering circuit; A first end of the first discharge circuit is connected to a second end of the first capacitor and a drain of the first transistor; A first end of the first voltage stabilizing protection circuit is connected to the power supply, and a second end of the first voltage stabilizing protection circuit is connected to the first charging circuit; The first output matching circuit and the first filtering circuit are connected in sequence.

3. The circuit according to claim 2, characterized in that When the gate-source voltage of the first transistor reaches a first threshold, discharging the first capacitor and the gate-drain capacitor based on the first discharge circuit; A first discharge time of the first discharge circuit for the first capacitor and the gate-drain capacitor is greater than a second discharge time of the first discharge circuit for the gate-drain capacitor.

4. The circuit according to claim 1, characterized in that The first charging circuit includes at least one charging resistor and a first diode; The at least one charging resistor is connected in parallel with the first diode.

5. The circuit according to claim 1, characterized in that The first transistor is a P-type MOSFET tube.

6. The circuit according to claim 2, characterized in that The first discharge circuit is composed of at least one discharge resistor.

7. The circuit according to claim 2, characterized in that The first voltage stabilizing protection circuit includes at least one voltage stabilizing resistor and at least one voltage stabilizing tube; The at least one voltage-stabilizing resistor and the at least one voltage-stabilizing tube are connected in parallel.

8. The circuit according to claim 2, characterized in that The first output matching circuit includes at least one polar capacitor and at least one non-polar capacitor; The polar capacitor and the non-polar capacitor are grounded and connected in parallel.

9. The circuit according to claim 2, characterized in that The first filter circuit is composed of a first filter capacitor, a second filter capacitor and a first filter inductor; The first filter capacitor and the second filter capacitor are connected in parallel and then grounded, and the first filter inductor and the second filter capacitor are connected in series and then grounded.

10. A chip, characterized in that: The chip comprises the startup circuit as described in any one of claims 1-9.

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