voltage regulator

Abstract

A voltage regulator includes: a reference current generator coupled between a power supply terminal and a reference terminal and configured to provide a reference current that is independent of an operating range of a power supply voltage; and a regulator stage including: a current terminal configured to receive the reference current; an NMOS transistor having a gate coupled to the current terminal, a drain coupled to the power supply terminal, and a source coupled to an output terminal; a reference voltage circuit coupled between the output terminal and the reference terminal for providing a regulated output voltage, the reference voltage circuit including an output resistor coupled in series with a conductive channel of an output bipolar transistor arranged in a diode-connected configuration; and an input bipolar transistor having a conductive channel coupled between the current terminal and the reference terminal and a base terminal coupled to the base terminal of the output bipolar transistor.

Description

Technical Field

[0001] The present disclosure relates to a voltage regulator, and in particular, to a voltage regulator for a battery management system. Summary of the Invention

[0002] According to a first aspect of the present disclosure, a voltage regulator is provided, comprising:

[0003] a power supply terminal configured to receive a power supply voltage;

[0004] Reference end;

[0005] an output terminal configured to provide a regulated output voltage;

[0006] a reference current generator coupled between the power supply terminal and the reference terminal and configured to provide a reference current that is independent of an operating range of the power supply voltage; and

[0007] The regulator stage, which includes:

[0008] a current terminal configured to receive the reference current from the reference current generator;

[0009] NMOS transistors having:

[0010] a gate terminal coupled to the current terminal;

[0011] a drain terminal coupled to the power terminal; and

[0012] a source terminal coupled to the output terminal;

[0013] a reference voltage circuit coupled between the output terminal and the reference terminal and configured to provide the regulated output voltage, the reference voltage circuit comprising a first output resistor coupled in series with a conductive channel of an output bipolar transistor, wherein the output bipolar transistor is arranged in a diode-connected configuration;

[0014] an input bipolar transistor having a conductive channel coupled between the current terminal and the reference terminal, and a base terminal coupled to the base terminal of the output bipolar transistor such that the input bipolar transistor and the output bipolar transistor form a bipolar current mirror to mirror the reference current through the reference voltage circuit.

[0015] The disclosed voltage regulator provides a low-impedance output that enables fast transient response to strong line or load regulation changes. If the load current decreases in a stepwise manner, the negative feedback loop of the regulator stage can respond quickly to maintain the regulated output voltage. The low-impedance output also reduces sensitivity to changes in load mismatch.

[0016] The NMOS transistor, the bipolar current mirror, and the first output resistor may be arranged in a negative feedback loop and configured to pull a mirrored reference current from the NMOS transistor through the first output resistor and the output bipolar transistor.

[0017] The negative feedback loop can draw a large current from the power supply through the NMOS transistor, thereby maintaining a fixed regulator output voltage with high accuracy over a wide load current range (up to tens of mA).

[0018] In one or more embodiments, the input bipolar transistor and the output bipolar transistor may be matched with bipolar transistors of the reference current generator.The first output resistor may be matched with an output current resistor of the reference current generator.

[0019] Matching the bipolar transistors and resistors of the reference current generator and regulator stages provides a highly accurate output voltage that is insensitive to any variations in process, temperature, or environment.

[0020] In one or more embodiments, the input bipolar transistor and the output bipolar transistor can be matched with the bipolar transistor of the reference current generator by each transistor having one or more of the same type, the same temperature coefficient, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same position on the layout. The first output resistor can be matched with the output current resistor of the reference current generator by each resistor having one or more of the same type, the same temperature coefficient, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same position on the layout.

[0021] In one or more embodiments, the resistance of the first output resistor may be selected such that a voltage across the first output resistor after receiving a mirror reference current compensates for a complementary to absolute temperature (CTAT) voltage component of the output bipolar transistor.

[0022] In one or more embodiments, the ratio of the effective size of the output bipolar transistor to the effective size of the input bipolar transistor can be selected so that the voltage across the first output resistor after receiving the mirror reference current compensates for the CTAT voltage component of the output bipolar transistor.

[0023] In one or more embodiments, the reference voltage circuit may include one or more additional reference voltage blocks coupled in series with the first output resistor and the output bipolar transistor between the output terminal and the reference terminal. Each additional reference voltage block may include:

[0024] another output resistor; and

[0025] Another bipolar transistor is arranged to have a conductive channel connected in series with the further output resistor.

[0026] In one or more embodiments, the further bipolar transistor may be arranged in a diode-connected configuration.

[0027] In one or more embodiments, the further reference voltage block may include:

[0028] a first further voltage dividing resistor coupled between a base terminal of the further bipolar transistor and a first conductive channel terminal of the further bipolar transistor; and

[0029] A second another voltage-dividing resistor is coupled between the base terminal of the another bipolar transistor and a second conductive channel terminal of the another bipolar transistor.

[0030] In one or more embodiments, the resistance of each further output resistor may be selected such that the voltage across the further output resistor after receiving the mirror reference current compensates for the complementary to absolute temperature CTAT voltage component of the corresponding further bipolar transistor.

[0031] In one or more embodiments, each further bipolar transistor may be matched with the output bipolar transistor and the bipolar transistor of the reference current generator. Each further output resistor may be matched with the first output resistor and the output current resistor of the reference current generator.

[0032] In one or more embodiments, each of the other bipolar transistors can be matched with the output bipolar transistor and the bipolar transistor of the reference current generator by each transistor having one or more of the same type, the same temperature coefficient, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same position on the layout. Each of the other output resistors can be matched with the first output resistor and the output current resistor of the reference current generator by each resistor having one or more of the same type, the same temperature coefficient, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same position on the layout.

[0033] In one or more embodiments, the another bipolar transistor may be an NPN bipolar transistor.

[0034] In one or more embodiments, the input bipolar transistor and the output bipolar transistor may be NPN bipolar transistors.

[0035] In one or more embodiments, the reference current generator may include:

[0036] Bias resistor;

[0037] a first bipolar transistor;

[0038] a second bipolar transistor;

[0039] a third bipolar transistor;

[0040] a fourth bipolar transistor; and

[0041] Output current resistor,

[0042] in:

[0043] The bias resistor is coupled to the power supply terminal and is configured to provide a bias current to the conductive channel of the fourth bipolar transistor;

[0044] The conductive channel of the fourth bipolar transistor is connected between the bias resistor and the first node;

[0045] The conductive channel of the third bipolar transistor is connected between the first node and the reference terminal;

[0046] The output current resistor is coupled between the reference terminal and the conductive channel of the first bipolar transistor;

[0047] The conductive channel of the first bipolar transistor is connected between the output current resistor and a second node;

[0048] The conductive element of the second bipolar transistor is coupled between the second node and the reference current output terminal;

[0049] a base terminal of the fourth bipolar transistor connected to the base terminal of the second bipolar transistor;

[0050] a base terminal of the third bipolar transistor connected to the second node;

[0051] a base terminal of the first bipolar transistor is connected to the first node; and

[0052] The fourth bipolar transistor is arranged in a diode-connected configuration.

[0053] In one or more embodiments, the resistance value of the first output resistor may be based on the resistance value of the output current resistor and a temperature coefficient of a collector-emitter voltage of the output bipolar transistor.

[0054] In one or more embodiments, the resistance value of the first output resistor may be based on the resistance value of the output current resistor, the ratio of the effective size of the input bipolar transistor to the effective size of the output bipolar transistor, the ratio of the effective size of the first bipolar transistor to the effective size of the second bipolar transistor, the temperature coefficient of the thermal voltage of the first bipolar transistor, and the temperature coefficient of the collector-emitter voltage of the output bipolar transistor.

[0055] In one or more embodiments, the resistance value of each further output resistor may be based on the resistance value of the output current resistor and a temperature coefficient of a collector-emitter voltage of the corresponding further bipolar transistor.

[0056] In one or more embodiments, the resistance value of each another output resistor is based on the resistance value of the output current resistor, the ratio of the effective size of the input bipolar transistor to the effective size of the output bipolar transistor, the ratio of the effective size of the first bipolar transistor to the effective size of the second bipolar transistor, the temperature coefficient of the thermal voltage of the first bipolar transistor, and the temperature coefficient of the collector-emitter voltage of the corresponding another bipolar transistor.

[0057] In one or more embodiments, the reference current generator may further include a PMOS mirror configured to mirror the reference current from the reference current output terminal to the regulator stage.

[0058] In one or more embodiments, the resistance values ​​of the first output resistor and any additional output resistors are further based on an effective magnitude ratio of a PMOS current mirror.

[0059] In one or more embodiments, the first to fourth bipolar transistors may be NPN bipolar transistors.

[0060] In one or more embodiments, based on the temperature coefficient of the output current resistor, the reference current generator may be one of the following:

[0061] PTAT current generator proportional to absolute temperature;

[0062] a complementary to absolute temperature (CTAT) current generator; and

[0063] Temperature-independent current generator.

[0064] In one or more embodiments, the effective sizes of the second, third, and fourth bipolar transistors may be substantially the same.

[0065] In one or more embodiments, the effective size of the first bipolar transistor may be greater than the effective size of the second bipolar transistor.

[0066] In one or more embodiments, the regulator stage may further include a feedback capacitor coupled between the gate of the NMOS transistor and the reference terminal.

[0067] In one or more embodiments, the voltage regulator may further include an output capacitor coupled between the output terminal and the reference terminal.

[0068] According to a second aspect of the present disclosure, there is provided a battery management system comprising any one of the voltage regulators disclosed herein.

[0069] According to another aspect of the present disclosure, a voltage regulator is provided, comprising:

[0070] a power supply terminal configured to receive a power supply voltage;

[0071] Reference end;

[0072] an output terminal configured to provide a regulated output voltage;

[0073] a reference current generator coupled between the power supply terminal and the reference terminal and configured to provide a reference current that is independent of an operating range of the power supply voltage; and

[0074] a regulator stage configured to receive the reference current from the reference current generator, the regulator stage comprising:

[0075] an NMOS transistor having a conductive channel coupled between the power supply terminal and the output terminal;

[0076] bipolar current mirror; and

[0077] The first output resistor,

[0078] wherein the conductive channel of the output bipolar transistor of the bipolar current mirror and the first output resistor are coupled in series between the output terminal and the reference terminal to form a reference voltage circuit configured to provide a regulated output voltage, and wherein the NMOS transistor, the bipolar current mirror and the first output resistor are arranged in a negative feedback loop and are configured such that the first output resistor and the output bipolar transistor pull a mirrored reference current from the NMOS transistor.

[0079] While the present disclosure is susceptible of various modifications and alternative forms, the features of the present disclosure have been illustrated by way of example in the drawings and will be described in detail. However, it should be understood that other embodiments besides the specific embodiments described are possible. All modifications, equivalents, and alternative embodiments falling within the spirit and scope of the appended claims are also encompassed.

[0080] The above discussion is not intended to represent every example embodiment or every implementation within the scope of the current or future claim sets. The following descriptions of the figures and detailed description further illustrate various example embodiments. The various example embodiments can be more fully understood by considering the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] One or more embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0082] Figure 1 shows the distribution of regulated output voltage of the pre-regulator with and without overvoltage and undervoltage detection requirements;

[0083] Figure 2 A voltage regulator according to an example embodiment of the present disclosure is shown;

[0084] Figure 3 Another voltage regulator according to an example embodiment of the present disclosure is shown;

[0085] Figure 4 shows another reference voltage block according to an example embodiment of the present disclosure; and

[0086] Figure 5 Another voltage regulator according to an example embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0087] Integrated circuits (ICs) operating in high-voltage environments with a large input supply operating range may require a first voltage regulator or pre-regulator to enable optimization of subsequent regulator stages, such as by using lower-voltage devices to optimize die size area. One such environment is battery management systems (BMS) for electric and hybrid vehicles.

[0088] Requirements for the preregulator may include very low current consumption to support the IC sleep mode current consumption, while being able to supply a large load current range when the IC is in full power mode.

[0089] The regulated output voltage of the pre-regulator may also have stringent accuracy requirements over variations in temperature, process, input / supply voltage, and load to support minimum load voltage requirements and maximum voltage ratings (to allow load functionality to be designed in with lower voltage devices).

[0090] In some applications, such as BMS, safety may also be a mandatory requirement, and pre-regulator output voltage monitoring may be required. This can include overvoltage and undervoltage detection. Therefore, the distribution range of overvoltage and undervoltage over process, temperature, voltage, and mismatch should not overlap with the distribution of the pre-regulator output voltage to prevent false error detection. In other words, the overvoltage and undervoltage distributions should be independent of the regulated output voltage distribution of the pre-regulator, and all three distributions should fit between the highest rated voltage limit and the lowest load voltage.

[0091] Figure 1 The distributions of regulated output voltages 101 and 103 for pre-regulators with and without overvoltage and undervoltage detection requirements are shown. The left curve illustrates the distribution requirements for a pre-regulator without safety requirements for overvoltage or undervoltage detection. The distribution of the pre-regulator's regulated output voltage 103 only needs to be between the highest rated voltage 105 and the lowest rated voltage 107 for functionality, centered around the nominal output voltage 109. The right curve illustrates the distribution requirements for a pre-regulator with safety requirements for overvoltage or undervoltage regulation. An example of such a requirement is the Automotive Safety Integrity Level D (ASIL-D) required for a BMS. The required distribution of the regulated output voltage 101, centered around the nominal output voltage 109, is much narrower, ensuring space for the overvoltage distribution 111 and the undervoltage distribution 113 between the upper rated value 105 and the lower rated value 107, without any overlap between the three distributions 101, 111, and 113. Obtaining such an accurate distribution of the regulated output voltage 101 can be challenging when no reference voltage or bias current is available. This can be especially challenging in high voltage environments where a low power output is required for a downstream regulator, such as in a BMS.

[0092] The voltage regulator of the present disclosure can meet the stringent requirements outlined above and provide a regulated output voltage with a narrow distribution over temperature, supply voltage and load. The regulator can provide up to tens of mA of load current and has a low quiescent current of less than 15 μA.

[0093] Figure 2 A voltage regulator 200 according to an embodiment of the present disclosure is shown.

[0094] The voltage regulator 200 is configured to receive a power supply voltage Vpwr having a large operating range at a power supply terminal 204 and provide a regulated output voltage V out In a wide load current range (0 to tens of mA) and for a large supply voltage operating range (10 to 70 V), the regulated output voltage V outIt is possible to have reduced temperature sensitivity and obtain a narrow voltage distribution (7.5 V ± 4% at 6σ in this example).The voltage regulator may also have a low quiescent current.

[0095] The voltage regulator 200 includes a reference current generator 202 coupled between a power supply terminal 204 and a reference terminal 206. The reference current generator is configured to provide a reference current I REF The operating range of the power supply voltage refers to the power supply voltage range when the voltage regulator 200 operates. In this example, the operating range of the power supply voltage is 10V to 70V.

[0096] In this example, the reference current generator 202 includes a bias resistor 250, a first bipolar transistor Q0 252, a second bipolar transistor Q1 254, a third bipolar transistor Q2 256, a fourth bipolar transistor Q3 258, and an output current resistor 260. In this example, the reference current generator 202 includes NPN bipolar transistors. The bias resistor 250, the first to fourth bipolar transistors 252, 254, 256, 258, and the output resistor 260 generate a first reference current I at a reference current output terminal 266. REF-1 .

[0097] Bias resistor 250 is coupled to power supply terminal 204 and to reference terminal 206 via third bipolar transistor 256 and fourth bipolar transistor 258. Bias resistor 250 is configured to provide a bias current to the collector terminal of fourth bipolar transistor 258. In this example, the bias resistor includes a first bias resistor R1 and a second bias resistor R2. If the first bias resistor and the second bias resistor each have a resistance value of 20 MΩ, and the power supply voltage Vpwr has an operating range that can vary between 10 V and 70 V, the bias current provided to fourth bipolar transistor 258 will vary between 200 nA and 1.75 μA.

[0098] The first to fourth bipolar transistors are arranged as follows: the collector terminal of the fourth bipolar transistor 258 is connected to the bias resistor 250; the fourth bipolar transistor is arranged in a diode-connected configuration, wherein the base terminal and the collector terminal of the fourth bipolar transistor 258 are connected together; the emitter terminal of the fourth bipolar transistor 258 is connected to the collector terminal of the third bipolar transistor 256 at the first node 262; the emitter terminal of the third bipolar transistor 256 is connected to the reference terminal 206; the output current resistor R i260 is coupled between the reference terminal 206 and the emitter terminal of the first bipolar transistor 252; the collector terminal of the first bipolar transistor 252 is connected to the emitter terminal of the second bipolar transistor 254; the collector terminal of the second bipolar transistor 254 is coupled to the reference current output terminal 266; the base terminal of the fourth bipolar transistor 258 is connected to the base terminal of the second bipolar transistor 254; the base terminal of the third bipolar transistor 256 is connected to the emitter terminal of the second bipolar transistor 254 and the collector terminal of the first bipolar transistor 252 at a second node 262; and the base terminal of the first bipolar transistor 252 is connected to the emitter terminal of the fourth bipolar transistor 258 and the collector terminal of the third bipolar transistor 256 at a first node 260.

[0099] In this example, the ratio of the effective sizes of the first bipolar transistor 252 to the second bipolar transistor 254, the third bipolar transistor 256, and the fourth bipolar transistor 258 is 8:1:1:1. Here, the effective size may refer to the size of the components on the semiconductor die. For example, the effective size of the bipolar transistors can be increased by stacking multiple bipolar transistors in parallel that have common base, collector, and emitter terminals.

[0100] Kirchoff's voltage law allows the base-emitter voltage VBE of the first to fourth bipolar transistors 252, 254, 256, 258 to be Q The first reference output current I REF-1 ,as follows:

[0101] I REF-1 R+VBE Q0 +VBE Q3 =VBE Q1 +VBE Q2

[0102] Assuming that the base current of the bipolar transistor is negligible compared to the bias current and the first reference current, we have:

[0103] I REF-1 ·R i +VBE Q0 =VBE Q1

[0104]

[0105]

[0106] Where V T and I S are the thermal voltage and saturation current of the bipolar transistor, respectively. The factors in Eq. Defines the ratio of the effective size of the first bipolar transistor 252 to the effective size of the second bipolar transistor 254 (in this example, ). Therefore, the first reference current I REF-1 The output current is determined only by the resistance value Ri of the output current resistor 260 and the ratio of the first bipolar transistor 252 to the second bipolar transistor 254. The first reference current I REF-1 Independent of any variations of the supply voltage Vpwr, this can be particularly advantageous in battery management systems.

[0107] In addition to being independent of the power supply voltage Vpwr, the first reference current I REF-1 The temperature dependence (or coefficient) of the first reference current (dI RREF-1 / dT) will depend on the temperature dependence of the thermovoltage (dV T / dT) and the temperature dependence of the output current resistor 260 (dRi / dT). The temperature dependence of the thermal voltage is usually a positive constant (V T =k h T / q (26mV, at 25°C)). Therefore, a first reference current I is provided. REF-1 and reference current I REF The reference current generator 202 can be one of the following: (i) a PTAT current generator that is proportional to absolute temperature; (ii) a CTAT current generator that is complementary to absolute temperature; or a temperature-independent current generator that depends on dR i / dT and dV T For example, if the output current resistor 260 is independent of temperature (dRi / dT=0), the reference current generator 202 will be a PTAT current generator.

[0108] The reference current generator 202 can provide a first reference current I to the regulator stage 208. REF-1 As a reference current. In this example, the additional high voltage mirror 268 is used to control the first reference current I REF-1 Mirror processing is performed to generate a reference current I REF In this example, the high voltage mirror is a PMOS mirror, but in other examples, the high voltage mirror may include other components such as a PNP transistor. The PMOS mirror includes: a first PMOS transistor having a conductive path coupled between the power supply terminal 204 and the reference current output terminal 266; and a second PMOS transistor having a conductive path coupled between the power supply terminal and the current terminal 210 of the regulator stage 208. The gate of the first PMOS transistor is connected to the gate of the second PMOS transistor and the reference current output terminal 266. In this example, the ratio of the effective size of the second PMOS transistor to the effective size of the first PMOS transistor is is 2:1, so that the reference current I REF is the first reference current I REF-1 twice as much.

[0109] The voltage regulator 200 further includes a regulator stage 208. The regulator stage 208 includes a reference current I REF The output terminal 212 is connected to the reference terminal 206, thereby forming a circuit for providing a regulated output voltage V out The input bipolar transistor 216 and the output bipolar transistor 218 form a bipolar current mirror. The NMOS transistor 214, the bipolar current mirror 216, 218, and the first output resistor 220 are arranged in a negative feedback loop to pull a mirrored reference current from the NMOS transistor 214 through the first output resistor 220 and the output bipolar transistor 218.

[0110] NMOS transistor 214 has a gate terminal coupled to current terminal 210, a drain terminal coupled to power terminal 204, and a source terminal coupled to output terminal 212. NMOS transistor 214 may have a rated voltage higher than a maximum value of an operating range of power supply voltage Vpwr.

[0111] A reference voltage circuit 222 coupled between the output terminal 212 and the reference terminal 206 includes a first output resistor 220 coupled in series with the conduction channel of an output bipolar transistor 218. In this example, the output bipolar transistor 218 is arranged in a diode-connected configuration with the base terminal connected to the first conduction channel terminal (the collector terminal of the NPN transistor).

[0112] In this example, a first conductive channel terminal of output bipolar transistor 218 is coupled to reference terminal 206, and a second conductive channel terminal of output bipolar transistor 218 is coupled to a first end of first output resistor 220. A second end of first output resistor 220 is coupled to output terminal 212 directly or through one or more additional reference voltage blocks 224.

[0113] The conductive channel of the input bipolar transistor 216 is coupled between the current terminal 210 and the reference terminal 206. The base terminal of the input bipolar transistor 216 is coupled to the base terminal of the output bipolar transistor 218, thereby forming a bipolar current mirror. In this way, the bipolar current mirror can be used to control the reference current I REFThe mirroring process is performed to generate a mirror reference current in the reference voltage circuit 222. In other words, the bipolar current mirror can pull the mirror reference current from the NMOS transistor 214 to the reference terminal 206 through the reference voltage circuit 222.

[0114] The effective size of the output bipolar transistor 218 may be different from the effective size of the input bipolar transistor 216. Here, the effective size may relate to the size of the components on the semiconductor die. For example, the effective size of the bipolar transistors may be increased by stacking multiple bipolar transistors in parallel having common base, collector, and emitter terminals. In this example, the ratio of the effective size of the output bipolar transistor 218 to the effective size of the input bipolar transistor is is 4:1. Therefore, the mirror reference current can be the reference current I REF In this way, the bipolar current mirrors 216, 218 and the NMOS transistor 214 form a negative feedback loop, thereby forcing four times the reference current I REF As a mirror reference current through the reference voltage circuit.

[0115] In the example shown, the input bipolar transistor 216 and the output bipolar transistor 218 are NPN transistors. In one or more examples, the properties (or type) of the bipolar transistors 216, 218 and the first output resistor 220 of the regulator stage 208 can be the same as the bipolar transistors 252, 254, 256, 258 and the output current resistor 260 of the reference current generator 202, respectively. In other words, the bipolar transistors and resistors of the regulator stage 208 can be matched to the bipolar transistors and resistors used in the reference current generator 202. This matching can include the bipolar transistors and resistors sharing the same properties or type (NPN / PNP transistors, polysilicon fused metal layer resistors, etc.), the same temperature coefficient / temperature dependency, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same location on the layout, as is known in the art. This matching of the components of the regulator 208 and the reference current generator 202 can compensate for process variations and provide the same component temperature dependency. For example, any process variations in the components of the reference current generator 202 that result in variations in the nominal reference current or its temperature dependence will be compensated for by corresponding process variations in the components of the regulator stage 208 .

[0116] In this example, the input bipolar transistor 216 and the output bipolar transistor 218 as well as the first to fourth bipolar transistors 252, 254, 256, 258 are all of the same type. Therefore, all bipolar transistors share their collector-emitter voltage dV CE / dT (or base-emitter voltage dV BESimilarly, the first output resistor 228 and the output current resistor 260 are of the same type, and their resistances R, Ri share the same temperature coefficient (dR / dT).

[0117] The collector-emitter voltage V across the diode-connected output bipolar transistor 218 CE Equal to the base-emitter voltage V BE . Collector-emitter voltage V CE (or in a diode configuration, the base-emitter voltage V BE ) may include a fixed bandgap voltage and a complementary to absolute temperature CTAT voltage component that is inversely related to temperature. In this example, the NPN output bipolar transistor 218, arranged in a diode-connected configuration, has a fixed bandgap voltage of approximately 1.25V.

[0118] When the mirror reference current flows through the reference voltage circuit 222, the output bipolar transistor 218 and the first output resistor 220 have a negative effect on the regulated output voltage V out The contribution can be written as:

[0119]

[0120] In this equation, R is the resistance value of the first output resistor 220. As described above, the reference current I REF The thermal voltage V of the bipolar transistor of the reference current generator 202 T Divide the output current by the resistance R of resistor 260 i Since the output current resistor 260 and the first output resistor 220 are of the same type and have the same temperature dependence (dR / dT=dRi / dT), the temperature dependence of the first term of the above equation depends on the thermal voltage V as a positive constant. T The first term of the equation therefore defines the PTAT voltage source. The regulated output voltage V out The sum of the PTAT voltage source and the CTAT voltage source is included. Therefore, the resistance value R of the first output resistor 220 can be selected to compensate the voltage V across the output bipolar transistor 218. CE (In this example, V BE ) temperature coefficient. Therefore, the diode-connected output bipolar transistor 218 and the first output resistor 220 have a significant effect on the regulated output voltage V out The contribution of may be insensitive to temperature variations and is equal to a fixed bandgap voltage of 1.25V. Therefore, the reference voltage circuit 222 of the voltage regulator 200 can provide a regulated output voltage V that is independent of temperature. out .

[0121] To balance the CTAT voltage component of the output bipolar transistor 218, the resistance value R of the first output resistor 220 may be based on the resistance Ri of the output current resistor 260, the effective size ratio of the first bipolar transistor 252 and the second bipolar transistor 254. The effective size of the PMOS current mirror 268 (where applicable) is greater than The effective magnitude ratio of the bipolar current mirrors 216 and 218 is The thermal voltage V of the bipolar transistor of the reference current generator 202 T The temperature coefficient of the collector-emitter voltage across the output bipolar transistor 216 (dV CE / dT). Figure 2 The relationship for a specific example of can be derived as follows:

[0122]

[0123]

[0124]

[0125]

[0126] Therefore, the resistance value R of the first output resistor 220 can be selected based on the resistance Ri of the output current resistor 260, the temperature coefficient of the thermal voltage (dV T / dT), the collector-emitter voltage temperature coefficient of the output bipolar transistor (dV CE / dT) and (where applicable) the scaling ratio of the voltage regulator 200 To balance the CTAT voltage component of the output bipolar resistor. Similarly, the ratio of resistance R / Ri can also be selected. Similarly, the resistance value R of the first output resistor 220, the resistance Ri of the output current resistor 260 and the scaling ratio of the voltage regulator 200 can also be selected. To balance the CTAT voltage components of the output bipolar transistors. Since there are many parameters that can be selected, there can be many different sets of values ​​that satisfy the above equation. Therefore, when selecting the values ​​of the parameters, other factors can be considered. For example, for Figure 2 The effective size ratio of the output bipolar transistor to the input bipolar transistor is Provides the best compromise between power dissipation, resistor size, and regulator speed (higher current provides lower output impedance and better load regulation).

[0127] In this way, the output voltage Vout of the voltage regulator 200 can be insensitive to temperature changes. Since the bipolar transistors and resistors shared by the reference current generator 202 and the regulator stage 208 are matched, the voltage regulator 200 can provide an output voltage Vout with high accuracy that is insensitive to any changes in process or environment. out .

[0128] In this example, regulator stage 208 also includes a feedback capacitor 221 coupled between the gate of NMOS transistor 214 and reference terminal 206. Feedback capacitor 221 can provide stability to voltage regulator 200. Regulator stage 208 also includes an output capacitor 223 coupled between output terminal 212 and reference terminal 206. Both feedback capacitor 221 and output capacitor 223 are on the order of a few picofarads and can be integrated on-chip. The low impedance provided by the presence of NMOS transistor 214 at output terminal 212 enables the use of such low capacitance while maintaining a stable circuit, particularly in response to load variations.

[0129] In some examples, the reference voltage circuit 222 may include only the output bipolar transistor 218 and the first output transistor 220. In this way, the reference voltage circuit 222 may provide a temperature-adjusted output voltage V that is equal to the fixed bandgap voltage of the output bipolar transistor 218. out In other examples where a higher output voltage is desired, the reference voltage circuit 222 may include one or more additional reference voltage blocks 224 .

[0130] Each additional reference voltage block 224 can include another bipolar transistor 226 and another output resistor 228. The other bipolar transistor 226 can be substantially identical to and of the same type as the output bipolar transistor. In this example, the other bipolar transistor 226 of each additional reference voltage block 224 includes an NPN bipolar transistor that is nominally identical to the output bipolar transistor 218. In this example, the other bipolar transistors 226 are arranged in a diode-connected configuration, however, in other examples, one or more of the other bipolar transistors 226 can be connected in other configurations, such as Figure 4 and 5 The further output resistor 228 may be substantially identical to the first output resistor 220 , being of the same type (fused polysilicon, metal film, etc.) and may have the same resistance value R.

[0131] In the same manner as described above for the output bipolar transistor / first output resistor pair, the voltage across each further resistor 228 can balance the collector-emitter voltage V across the corresponding further bipolar transistor 226. CE The CTAT component contributes to the regulated output voltage V outIn this way, each of the one or more additional reference voltage blocks 224 can contribute to the output voltage V out In this example, each additional reference voltage block can contribute to the output voltage V out provides an additional 1.25V contribution.

[0132] Figure 3 An example regulator stage 308 is shown having a reference voltage circuit 322 that includes five additional reference voltage blocks (N=5) in addition to the output bipolar transistor 318 and the first output resistor 320. The five additional reference voltage blocks are shown expanded. Each additional reference voltage block includes another output resistor 328-1, 328-2, ..328-5 that is nominally identical to the first output resistor 320 and the output bipolar transistor 318, respectively, and another diode-connected bipolar transistor 326-1, 326-2, ..326-5. The output bipolar transistor 318 and each of the other bipolar transistors 326-1, 326-2, ..326-5 are arranged in a diode-connected configuration, and the output voltage of the regulator stage 308 can be written as:

[0133]

[0134] V out =6·R·(4·I REF )+6·V BE

[0135] Therefore, if the resistance values ​​R of the first and further output resistors 320, 328-1, 328-2, ..328-5 are selected to equalize the voltage V across the respective output and further bipolar transistors 318, 326-1, 326-2, ..326-5 BE The CTAT voltage component, the regulated output voltage V out will be equal to six times the fixed bandgap voltage (6 x 1.25 = 7.5 V) and will be independent of temperature.

[0136] As discussed above, the one or more further bipolar transistors may be arranged in configurations other than a diode-connected configuration. Figure 4 Another reference voltage block 424 is shown having another bipolar transistor 426 connected in a resistor divider configuration according to other embodiments of the present disclosure.

[0137] Another reference voltage block 424 includes another output resistor 428 coupled in series with the conductive channel of another bipolar transistor 426, as described above with respect to FIG. Figure 2 and 3In addition, another reference voltage block 424 includes: a first voltage dividing resistor Ra 430 coupled between the base terminal of another bipolar transistor 426 and the first conductive channel terminal of another bipolar transistor 426; and a second voltage dividing resistor Rb 432 coupled between the base terminal of another bipolar transistor 426 and the second conductive channel terminal of another bipolar transistor 426.

[0138] The resistor divider configuration shown can be described as a k*VBE structure because it can supply any voltage higher than the fixed bandgap reference voltage of 1.25 V. Assuming that the resistance values ​​of the first and second divider resistors 430 and 432 are large enough so that the current flowing through the first and second divider resistors 430 and 432 is negligible compared to the current at the collector of the other bipolar transistor 428 (mirror reference current), the base-emitter voltage V BE To convert the collector-emitter voltage V CE writing:

[0139]

[0140] Therefore, after receiving the mirror reference current, the other reference voltage block 424 can provide a voltage that is equal to the base-emitter voltage V BE Proportional and greater than or equal to Figure 2 and 3 The collector-emitter voltage V of the classic diode-connected configuration shown in FIG provides 1.25V. CE As mentioned above about Figure 2 As described, the resistance value R of the other output resistor 428 may be selected f To compensate for the collector-emitter voltage V CE The equations and dependencies outlined above for determining the value of the first output resistor are generally applicable to determining the resistance value of the further output resistor 428. However, in Figure 4 In the example, the collector-emitter voltage V CE The CTAT coefficient may be different from the above Figure 2 and 3 The base-emitter voltage V BECTAT coefficient. Thus, in this example, the resistance value Rf of the further output resistor 428 may be different from the resistance value R of the first output resistor. However, the temperature dependence of the two resistors may remain the same (dR / dT=dRi / dT). Furthermore, in addition to the different resistance values ​​Rf, R, and the different connections of the transistors, each further bipolar transistor 426 and each further output resistor 428 is further matched to the output bipolar transistor and the first output resistor, respectively, and is also matched to the bipolar transistor and the output current resistor of the reference current generator, respectively. In this way, the further reference voltage block 424 can provide a regulated output voltage of any value greater than 1.25V that is independent of temperature and process.

[0141] Figure 5 Another voltage regulator 500 according to an embodiment of the present disclosure is shown. Figure 2 Shown in Figure 5 Features of the 500 series have been given corresponding reference numerals and will not need to be described again here.

[0142] In this example, the reference voltage circuit 522 includes a bipolar output transistor 518 and a first output resistor 520 arranged in a diode-connected configuration. The reference voltage circuit 522 also includes N (N=0, 1, 2, ...) further reference voltage blocks 524, each of which includes another bipolar transistor 526 and another output resistor 528. Each further bipolar transistor 526 is arranged Figure 4 The resistor divider configuration. Figure 5 The voltage regulator 500 can therefore provide a universal range of temperature-independent output voltages through appropriate selection of Ra, Rb, and N.

[0143] Figure 2 and 5 The disclosed voltage regulator can have an extremely low total quiescent current, even at high operating voltages of the supply voltage. The quiescent current is also independent of the load current. The quiescent current includes the current from Figure 2 and 5 The contributions of the four branches of the circuit are:

[0144] • The contribution from the first branch depends on the supply voltage Vpwr and has a maximum value of approximately 2 μA.

[0145] From carrying the first reference current I REF-1 The contribution of the second branch depends only on the temperature and resistance value R of the output current resistor 260 i And is typically about 1μA±20%.

[0146] ·From carrying reference current I REFThe contribution of the third branch is twice that of the second branch (due to the size ratio of the PMOS mirror 268 ) and is approximately 2μA±20%.

[0147] The contribution of the fourth branch carrying the mirror reference current is four times that of the third branch (due to the size ratio of the output bipolar transistor 218 to the input bipolar transistor 216). ) and is approximately 8μA±20%.

[0148] Therefore, for a load current of 0 to 20mA, Figure 2 and 5 A voltage regulator of 100 Ω may have a maximum quiescent current of approximately 15 μ A. This quiescent current is also independent of any load current.

[0149] For the disclosed voltage regulator, a high-voltage NMOS transistor, an input bipolar transistor, and a reference voltage circuit form the closed-loop regulator stage of the voltage regulator. The input bipolar transistor and the reference voltage circuit can be considered a feedback network. The feedback network can also include a feedback capacitor. The feedback network can be matched to the reference current generator. In other words, the bipolar transistors and resistors of the regulator stage can be matched to the bipolar transistors and resistors used in the reference current generator. This matching can include the bipolar transistors and resistors sharing the same type (NPN / PNP transistors, polysilicon melt, metal layer, etc. resistors), the same temperature dependencies, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same location on the layout, as is known in the art. This matching of the feedback network and the reference current generator can compensate for process variations and provide the same component temperature dependencies. For example, any process variation in the components of the reference current generator that causes a variation in the nominal reference current will be compensated by a corresponding process variation in the components of the regulator stage.

[0150] The negative feedback loop provided by the NMOS transistor and the feedback network can draw a large current from the power supply through the NMOS transistor, thereby maintaining a fixed regulator output voltage V with high accuracy over a wide load current range (up to tens of mA). out .For example, Figure 2 The voltage regulator maintains a regulated output voltage of 7.5V ±4% with a distribution / accuracy of 6σ. Furthermore, it provides accurate output voltage without the need for output trimming.

[0151] The disclosed voltage regulator provides a low impedance output that enables fast transient response to strong line regulation or load regulation changes. If the load current decreases in a stepwise manner, the negative feedback loop of the regulator stage can respond quickly to maintain the regulated output voltage V out The low impedance output also reduces sensitivity to changes in load mismatch.

[0152] The disclosed voltage regulator also provides a high power supply rejection ratio (PSSR) that maintains an accurately regulated output voltage distribution over a wide operating range of the power supply voltage Vpwr. The high PSSR can be maintained as long as the high-voltage NMOS transistor and the high-voltage PMOS current mirror (discussed below) have sufficient saturation margin.

[0153] In summary, the disclosed voltage regulator comprises the following arrangement:

[0154] 1. A reference current source with low sensitivity to input bias current and supply voltage variations; and

[0155] 2. A closed-loop regulator stage using a high-voltage NMOS pass device matched to a reference current source and a feedback network. This regulator stage can produce an output voltage proportional to the bandgap voltage using a scaling factor set by the circuit topology.

[0156] The disclosed voltage regulator can be considered as a self-referenced and self-biased voltage regulator with minimal quiescent current independent of any load current. The voltage regulator can provide an accurately regulated output voltage over a wide range of load currents and / or supply voltages.

[0157] The disclosed voltage regulator can be used in any power management IC operating in an environment with a wide input / supply voltage operating range. The disclosed voltage regulator can be particularly advantageous in applications where current consumption is critical, particularly at low loads. The disclosed voltage regulator can be particularly advantageous when used in battery management systems, such as those used in electric or hybrid vehicles.

[0158] The voltage regulator can support a wide high supply voltage range while delivering minimal low-power mode current consumption. In addition, the robustness and accuracy of the voltage regulator can simplify downstream voltage regulator stages and save die size.

[0159] Unless a specific order is explicitly stated, the instructions and / or flowchart steps in the above figures may be executed in any order. In addition, those skilled in the art will recognize that although an example instruction set / method has been discussed, the materials in this specification may be combined in various ways to produce other examples and should be understood within the context provided in this detailed description.

[0160] In some example embodiments, the instruction sets / method steps described above are implemented as functions and software instructions embodied as executable instruction sets that are implemented on a computer or a machine programmed and controlled with the executable instructions. Such instructions are loaded for execution on a processor (e.g., one or more CPUs). The term processor includes a microprocessor, a microcontroller, a processor module or subsystem (including one or more microprocessors or microcontrollers), or other control or computing devices. A processor may refer to a single component or a plurality of components.

[0161] In other examples, the instruction sets / methods described herein and the data and instructions associated therewith are stored in corresponding storage devices, which are implemented as one or more non-transient machine or computer readable or computer usable storage media. Such one or more computer readable or computer usable storage media are considered part of an article (or product). An article or product may refer to any manufactured single component or multiple components. As defined herein, non-transient machine or computer usable media does not include signals, but such media is capable of receiving and processing information from signals and / or other transient media.

[0162] Example embodiments of the materials discussed in this specification may be implemented in whole or in part via network, computer, or data-based devices and / or services. These may include the cloud, the Internet, an intranet, a mobile device, a desktop computer, a processor, a lookup table, a microcontroller, a consumer device, infrastructure, or other enabling devices and services. As may be used herein and in the claims, the following non-exclusive definitions are provided.

[0163] In one example, one or more instructions or steps discussed herein are automated. The terms automation or automatically (and similar variations thereof) mean the use of computers and / or mechanical / electrical devices to control the operation of equipment, systems, and / or processes without the need for human intervention, observation, effort, and / or decision-making.

[0164] It should be understood that any components referred to as being coupled may be coupled or connected directly or indirectly. In the case of an indirect coupling, additional components may be disposed between the two components referred to as being coupled.

[0165] In this specification, example embodiments have been presented based on a selected set of details. However, those skilled in the art will appreciate that many other example embodiments can be practiced that include different selected sets of these details. It is intended that the appended claims cover all possible example embodiments.

Claims

1. A voltage regulator, characterized in that: include: a power supply terminal configured to receive a power supply voltage; Reference end; an output terminal configured to provide a regulated output voltage; a reference current generator coupled between the power supply terminal and the reference terminal and configured to provide a reference current that is independent of an operating range of the power supply voltage; as well as The regulator stage, which includes: a current terminal configured to receive the reference current from the reference current generator; NMOS transistors having: a gate terminal coupled to the current terminal; a drain terminal coupled to the power terminal; and a source terminal coupled to the output terminal; a reference voltage circuit coupled between the output terminal and the reference terminal and configured to provide the regulated output voltage, the reference voltage circuit comprising a first output resistor coupled in series with a conductive channel of an output bipolar transistor, wherein the output bipolar transistor is arranged in a diode-connected configuration; an input bipolar transistor having a conductive channel coupled between the current terminal and the reference terminal, and a base terminal coupled to the base terminal of the output bipolar transistor such that the input bipolar transistor and the output bipolar transistor form a bipolar current mirror to mirror the reference current through the reference voltage circuit.

2. The voltage regulator according to claim 1, wherein: The input bipolar transistor and the output bipolar transistor are matched with the bipolar transistor of the reference current generator; and The first output resistor matches an output current resistor of the reference current generator.

3. The voltage regulator according to claim 2, wherein: The input bipolar transistor and the output bipolar transistor are matched to the bipolar transistor of the reference current generator by each transistor sharing the same type, the same temperature coefficient, the same manufacturing process, the same wafer, the same manufacturing time, and / or the same position on the layout; and The first output resistor is matched to the output current resistor of the reference current generator by each resistor sharing the same type, same temperature coefficient, same manufacturing process, same wafer, same manufacturing time and / or same position on the layout.

4. A voltage regulator according to any one of the preceding claims, characterized in that The reference voltage circuit includes one or more further reference voltage blocks coupled in series with the first output resistor and the output bipolar transistor between the output terminal and the reference terminal, each further reference voltage block including: another output resistor; and Another bipolar transistor is arranged to have a conductive channel connected in series with the further output resistor.

5. The voltage regulator according to claim 4, wherein: The further bipolar transistor is arranged in a diode-connected configuration.

6. The voltage regulator according to claim 4, wherein: The additional reference voltage block comprises: a first further voltage dividing resistor coupled between a base terminal of the further bipolar transistor and a first conductive channel terminal of the further bipolar transistor; and A second another voltage-dividing resistor is coupled between the base terminal of the another bipolar transistor and a second conductive channel terminal of the another bipolar transistor.

7. The voltage regulator according to claim 4, wherein: Each other bipolar transistor is matched to the output bipolar transistor and the bipolar transistor of the reference current generator; and Each further output resistor matches the first output resistor and an output current resistor of the reference current generator.

8. The voltage regulator according to claim 1, wherein: The reference current generator comprises: Bias resistor; a first bipolar transistor; a second bipolar transistor; a third bipolar transistor; a fourth bipolar transistor; and Output current resistor, in: The bias resistor is coupled to the power supply terminal and is configured to provide a bias current to the conductive channel of the fourth bipolar transistor; The conductive channel of the fourth bipolar transistor is connected between the bias resistor and the first node; The conductive channel of the third bipolar transistor is connected between the first node and the reference terminal; The output current resistor is coupled between the reference terminal and the conductive channel of the first bipolar transistor; The conductive channel of the first bipolar transistor is connected between the output current resistor and a second node; The conductive channel of the second bipolar transistor is coupled between the second node and a reference current output terminal; a base terminal of the fourth bipolar transistor connected to the base terminal of the second bipolar transistor; a base terminal of the third bipolar transistor connected to the second node; a base terminal of the first bipolar transistor is connected to the first node; and The fourth bipolar transistor is arranged in a diode-connected configuration.

9. The voltage regulator according to claim 8, wherein: The resistance value of the first output resistor is based on the resistance value of the output current resistor and a temperature coefficient of a collector-emitter voltage of the output bipolar transistor.

10. A battery management system, characterized in that: A voltage regulator as claimed in any preceding claim.

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