CN109358295B - Power failure indicating circuit applied to DC-DC - Google Patents
Power failure indicating circuit applied to DC-DC Download PDFInfo
- Publication number
- CN109358295B CN109358295B CN201811102946.3A CN201811102946A CN109358295B CN 109358295 B CN109358295 B CN 109358295B CN 201811102946 A CN201811102946 A CN 201811102946A CN 109358295 B CN109358295 B CN 109358295B
- Authority
- CN
- China
- Prior art keywords
- voltage
- comparison
- comparison voltage
- signal
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Dc-Dc Converters (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The invention discloses a power failure indicating circuit applied to DC-DC, which comprises a reference circuit, a DC-DC feedback network and a failure comparator circuit, wherein: the DC-DC feedback network receives the output voltage of the DC-DC, obtains a sensing voltage Vsense through resistance voltage division, and sends the feedback voltage Vsense to a fault comparison voltage; the reference circuit generates reference voltage, divides the reference voltage to obtain four comparison voltage signals and sends the four comparison voltage signals to the fault comparison circuit; and the fault comparison circuit compares the feedback voltage Vsense value with a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal respectively, wherein the feedback voltage Vsense is lower than the second comparison voltage or higher than the fourth comparison voltage in the rising process or is lower than the first comparison voltage or higher than the third comparison voltage in the falling process, and outputs an effective fault mark signal. The invention can effectively monitor the output voltage change of the DC-DC voltage drop type switching power supply.
Description
Technical Field
The invention relates to a power failure indicating circuit of a DC-DC switching converter, which is particularly applied to the environment with higher requirement on the precision of output voltage and wider working temperature range in a switching power supply.
Background
The output of the DC-DC switching converter is often used as a power supply for the whole system, and the stability of the DC-DC output voltage directly affects the working state of the whole system, so a power failure circuit needs to be designed to monitor the output voltage failure in real time.
In the system application, in order to detect the condition of a system power supply in real time, a power supply monitoring chip is required to be added in the system construction, so that the overall power consumption is increased and the area is increased for the overall system, and the development requirements of miniaturization and low power consumption of an integrated circuit are not met. Some of the existing DC-DC converter circuits do not contain a fault indication circuit, so that once the output VOUT is unstable or power failure occurs in the application process, the system cannot timely distinguish or process the situation. Secondly, the comparison voltage precision of the fault indication circuit integrated in the DC-DC is low, and the hysteresis value is realized by an internal comparator, so that the problem that the hysteresis value changes greatly along with the temperature is brought, and the anti-jamming capability of the comparison voltage is poor due to noise caused by frequent switching of an internal power tube in the normal working process of the DC-DC.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the defects of the prior art are overcome, and the power failure indicating circuit applied to the DC-DC is provided, so that the output voltage change of the DC-DC voltage drop type switching power supply is effectively monitored.
The technical solution of the invention is as follows: a power failure indication circuit for application to DC-DC, the circuit comprising a reference circuit, a DC-DC feedback network, a failure comparator circuit, wherein:
the DC-DC feedback network receives the output voltage of the DC-DC, obtains a feedback voltage Vsense through resistance voltage division, and sends the feedback voltage Vsense to a fault comparison voltage;
the fault comparator comprises a reference circuit, a fault comparison circuit and a control circuit, wherein the reference circuit generates reference voltage under the action of DC-DC power supply voltage, and obtains four comparison voltage signals through resistance voltage division of the reference voltage and sends the four comparison voltage signals to the fault comparison circuit, and the four comparison voltage signals are sequentially marked as a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal from small to large;
the fault comparison circuit is used for comparing the feedback voltage Vsense value with a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal respectively, wherein the voltage of the feedback voltage Vsense is lower than the second comparison voltage or higher than the fourth comparison voltage in the rising process, and outputting an 'effective' fault mark signal to indicate that the power supply has a fault, otherwise, outputting an 'ineffective' fault mark signal to indicate that the power supply does not have the fault; when the voltage of the feedback voltage Vsense is lower than the first comparison voltage or higher than the third comparison voltage in the falling process, outputting an effective fault mark signal to indicate that the DC-DC power supply has a fault; otherwise, an "invalid" fault flag signal is output indicating that there is no fault with the DC-DC power supply.
The reference circuit comprises a PMOS (P-channel metal oxide semiconductor) tube MP1, an operational amplifier OPA (operational amplifier), NPN (negative-positive-negative) triodes Q1 and Q2, resistors R11, R12, R13 and R14, a voltage dividing resistor string, a source electrode of the PMOS tube MP1 is connected with a power supply VDD, a grid electrode of the PMOS tube MP1 is connected with a bias voltage Vbias, a drain electrode of the PMOS tube MP1 is connected with the voltage dividing resistor string, and the drain electrode voltage of the PMOSBGThe electric groups R11 and R12 are commonly connected to a reference power supply VBGThe other ends are respectively connected with an operational amplifierThe emitter electrodes of triodes Q1 and Q2 are respectively connected with the same-direction end and the reverse end of the OPA, the base electrodes are connected with the divider resistor string, the collector electrode of Q2 is connected with a resistor R13, the collector electrode of Q13 is connected with the collector electrode of Q1 and one end of R14, the other end of R14 is connected with the ground, and the first comparison voltage, the second comparison voltage, the third comparison voltage and the fourth comparison voltage are formed by VREFThe voltage is obtained by voltage division through the voltage division resistor string.
The voltage dividing resistor string is resistors which are connected in series.
And a fixed voltage difference exists between the first comparison voltage signal and the second comparison voltage signal and between the third comparison voltage signal and the fourth comparison voltage signal, the fixed voltage difference is called as a hysteresis voltage, and the hysteresis voltage takes 3% -5% of the feedback voltage Vsense.
The second comparison voltage takes the values as follows:
the third comparison voltage takes the values as follows:
the fault comparison circuit comprises switches S1, S2, S3 and S4, comparators COMP1 and COMP2, buffers BUFF1 and BUFF2, inverters INV1, INV2, INV3, INV4 and INV5 and an exclusive-OR gate NOR 1;
the feedback voltage Vsense is simultaneously connected with the positive terminals of comparators COMP1 and COMP2, the first comparison voltage signal and the second comparison voltage signal are respectively connected with the negative terminal of a comparator COMP1 through switches S1 and S2, the output terminal of the comparator COMP1 is connected with a buffer BUFF1, and the output terminal of the buffer BUFF1 is connected with an inverter INV 1; the output end signal of the buffer BUFF1 and the output signal of the inverter INV1 are respectively used for feedback control of the switches S1 and S2;
the third comparison voltage signal and the fourth comparison voltage signal are respectively connected to the negative terminal of a comparator COMP2 through switches S3 and S4, the output terminal of the comparator COMP2 is connected with a buffer BUFF2, and the output terminal of the buffer BUFF2 is sequentially connected with an inverter INV2 and an inverter INV 3; the output end signal of the buffer BUFF2 and the output signal of the inverter INV2 are respectively used for feedback control of the switches S3 and S4;
the output ends of the inverter INV1 and the inverter INV3 are simultaneously connected to the input end of the xor gate NOR1, the output end of the xor gate is sequentially connected to the inverter INV4 and the inverter INV5, and the output of the inverter INV5 is a fault flag signal.
The fault comparison circuit also comprises resistors R1, R2, R3, R4 and R5, capacitors C1, C2, C3, C4 and C5,
the resistor R1 is connected between the feedback voltage Vsense and the positive terminal of the comparator COMP1, the resistor C1 is connected between the positive terminal of the comparator COMP1 and the ground, and the resistor R1 and the capacitor C1 form an RC filter circuit for filtering interference on the feedback voltage Vsense;
the resistor R2 is connected between the first comparison voltage signal and the switch S1, the C2 is connected between the first comparison voltage signal and the common end of the switch S1 to the ground, and the resistor R2 and the capacitor C2 form an RC filter circuit for filtering interference on the first comparison voltage signal;
the resistor R3 is connected between the first comparison voltage signal and the switch S2, the C2 is connected between the first comparison voltage signal and the common end of the switch S2 to the ground, and the resistor R3 and the capacitor C2 form an RC filter circuit for filtering interference on the second comparison voltage signal;
the resistor R4 is connected between the first comparison voltage signal and the switch S3, the C3 is connected between the first comparison voltage signal and the common end of the switch S3 to the ground, and the resistor R4 and the capacitor C3 form an RC filter circuit for filtering interference on the third comparison voltage signal;
the resistor R5 is connected between the first comparison voltage signal and the switch S4, the C4 is connected between the first comparison voltage signal and the common end of the switch S4 to the ground, and the resistor R5 and the capacitor C4 form an RC filter circuit for filtering interference on the fourth comparison voltage signal.
The DC-DC feedback network comprises an inductor L2, resistors R21 and R22, one end of the inductor L2 is connected with an output voltage signal of the DC-DC, the other end of the inductor L2 is connected with a resistor R21, a resistor R21 and a resistor R22 are connected in series and grounded, and a voltage division point between the resistor R21 and the resistor R22 is fed back to the fault comparison circuit to serve as a feedback voltage Vsense.
The DC-DC is a boost type switching power supply, a buck type switching power supply or a boost type switching power supply.
Compared with the prior art, the invention has the advantages that:
(1) the band-gap voltage comparator comprises a voltage comparator with hysteresis, wherein the comparison voltage is 4 comparison voltage signals which are formed by a band-gap reference circuit through a divider resistor and are irrelevant to temperature and power supply voltage, the hysteresis voltage is the difference value of 2 fixed comparison voltage signals and is 3% of feedback voltage, and compared with the traditional comparator with internal hysteresis, the hysteresis value of the comparator is less influenced by temperature and process and is simple to realize.
(2) The reference voltage of the invention obtains a reference voltage irrelevant to the power voltage and the temperature under the action of the power voltage, four reference comparison voltages are output after resistance voltage division, and when the environmental temperature is changed greatly and the requirement on the DC-DC output precision is higher in an application environment, a fault indication circuit is designed in the DC-DC circuit, so that the DC-DC output voltage, namely the power supply of the system is abnormal, can be judged in time;
(3) the reference voltage circuit adopts a core circuit power supply structure taking an auxiliary power supply VBG with good PSRR performance as a reference, so that error turnover of fault signals caused by reference voltage disturbance is prevented;
(3) because the switching tube in the DC-DC circuit is always in a switching state during working and the noise of the ground end is larger, the anti-noise design is added at the input end to prevent the fault signal from being mistakenly turned over due to the interference of the input signal;
(4) the fault mark signal can be used as an enabling signal of a next-stage DC-DC circuit to carry out sequencing of sequential electrification of a plurality of chips, and cascade configuration of multiple circuit electrification sequences is completed.
Drawings
FIG. 1 is a general block diagram of a power failure indication circuit for DC-DC applications of the present invention;
FIG. 2 is a simplified reference circuit according to an embodiment of the present invention;
FIG. 3 is a simplified diagram of a resistor divider string according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a fault indication circuit according to an embodiment of the present invention;
FIG. 5 is a diagram of a DC-DC feedback network according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a cascade configuration in a system application according to an embodiment of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific examples.
Fig. 1 is a power failure indication circuit for DC-DC application of the present invention, the circuit comprising a reference circuit, a DC-DC feedback network, a failure comparator circuit, wherein:
the DC-DC feedback network receives the output voltage of the DC-DC, obtains a feedback voltage Vsense through resistance voltage division, and sends the feedback voltage Vsense to a fault comparison voltage;
the fault comparator comprises a reference circuit, a fault comparison circuit and a control circuit, wherein the reference circuit generates reference voltage under the action of DC-DC power supply voltage, and obtains four comparison voltage signals through resistance voltage division of the reference voltage and sends the four comparison voltage signals to the fault comparison circuit, and the four comparison voltage signals are sequentially marked as a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal from small to large;
the fault comparison circuit is used for comparing the feedback voltage Vsense value with a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal respectively, wherein the voltage of the feedback voltage Vsense is lower than the second comparison voltage or higher than the fourth comparison voltage in the rising process, and outputting an 'effective' fault mark signal to indicate that the power supply has a fault, otherwise, outputting an 'ineffective' fault mark signal to indicate that the power supply does not have the fault; when the voltage of the feedback voltage Vsense is lower than the first comparison voltage or higher than the third comparison voltage in the falling process, outputting an effective fault mark signal to indicate that the DC-DC power supply has a fault; otherwise, outputting an 'invalid' fault flag signal to indicate that the DC-DC power supply has no fault, and outputting the fault flag signal to a next-stage circuit.
And a fixed voltage difference exists between the first comparison voltage signal and the second comparison voltage signal and between the third comparison voltage signal and the fourth comparison voltage signal, the fixed voltage difference is called as a hysteresis voltage, and the hysteresis voltage takes 3% -5% of the feedback voltage Vsense.
The second comparison voltage takes the values as follows:
the third comparison voltage takes the values as follows:
for example, the first comparison voltage signal is 91% feedback voltage Vsense, the second comparison voltage signal is 94% feedback voltage Vsense, the third comparison voltage signal is 106% feedback voltage Vsense, and the fourth comparison voltage signal is 109% feedback voltage Vsense. I.e. below the feedback voltage Vsense, there is a 3% hysteresis voltage during the rise and fall. In the process of rising the feedback voltage Vsense, when the feedback voltage Vsense is higher than the second comparison voltage and lower than the fourth comparison voltage, the power supply is in a normal condition and does not have a fault; when the feedback voltage Vsense is reduced and is higher than the first comparison voltage and lower than the third comparison voltage, the power supply is in a normal state and does not have a fault. And the other conditions are that the power supply fails.
As shown in fig. 2, the reference circuit includes a PMOS transistor MP1, an operational amplifier OPA, NPN triodes Q1 and Q2, resistors R11, R12, R13 and R14, a voltage dividing resistor string, a source of the PMOS transistor MP1 connected to a power supply VDD, a gate connected to a bias voltage Vbias, such that the PMOS transistor MP1 operates in a saturation region, a drain connected to the voltage dividing resistor string, and a drain voltage of the PMOS transistor MP1 as a reference power supply VRGThe electric groups R11 and R12 are commonly connected to a reference power supply VBGThe other end of the operational amplifier is connected with the same-direction end and the reverse-direction end of the OPA respectively, the emitting electrodes of the triodes Q1 and Q2 are connected with the same-direction end and the reverse-direction end of the OPA respectively, the base electrodes are connected with the voltage dividing resistor string, the collector electrode of Q2 is connected with the resistor R13, the collector electrode of Q13 is connected with the collector electrode of Q1 and one end of R14, the other end of R14 is connected with the ground, and the first comparison voltage, the second comparison voltage, the third comparison voltage and the fourth comparison voltage are respectively formed byREFThe voltage is obtained by voltage division through the voltage division resistor string.
As shown in fig. 3, the voltage dividing resistor string is resistors connected in series.
Because the reference circuit is a preferential power-on module of the whole chip, the power supply of the reference circuit is directly from the input voltage VDD of the port, and the VDD generates larger noise in the DC-DC operation, an auxiliary power supply V with good PSRR performance is adopted in the aspect of architecture selectionBGThe core circuit power supply structure for the benchmark prevents the fault signal from being turned over by mistake caused by the disturbance of the benchmark voltage.
Under the action of power supply voltage, the invention obtains a reference circuit and a power supplyVoltage and temperature independent reference voltage VREFAnd 4 comparison voltages are generated through resistance voltage division and output to a fault indication circuit, and the power supply voltage is the working voltage of DC-DC.
The principle formula of the reference voltage independent of temperature and power supply voltage is as follows, where VREFComprises the following steps:
I×R13＝VBE1-VBE2＝VT*lnn
wherein VRE1And VRE2For base-collector voltage, V, of the respective transistorTK is boltzmann constant, Q is the electron charge, and n is the emitter area ratio of Q2 and Q1. From the above expressions, the resistances of the resistors R13 and R14 are adjusted to cancel the V with the negative temperature characteristic and the positive temperature characteristicTVoltage, V can be obtainedREFThe voltage is a voltage independent of the supply voltage VDD and the temperature. V of the designBGThe voltage is 1.8V, VREFThe value was 1.2V. And the voltage division resistor string with low temperature coefficient is used for obtaining the 0.72V and 0.75V required by the design. 0.85V and 0.88V.
The fault comparison circuit comprises switches S1, S2, S3 and S4, comparators COMP1 and COMP2, buffers BUFF1 and BUFF2, inverters INV1, INV2, INV3, INV4 and INV5 and an exclusive-OR gate NOR 1;
the feedback voltage Vsense is simultaneously connected with the positive terminals of comparators COMP1 and COMP2, the first comparison voltage signal and the second comparison voltage signal are respectively connected with the negative terminal of a comparator COMP1 through switches S1 and S2, the output terminal of the comparator COMP1 is connected with a buffer BUFF1, and the output terminal of the buffer BUFF1 is connected with an inverter INV 1; the output end signal of the buffer BUFF1 and the output signal of the inverter INV1 are respectively used for feedback control of the switches S1 and S2;
the third comparison voltage signal and the fourth comparison voltage signal are respectively connected to the negative terminal of a comparator COMP2 through switches S3 and S4, the output terminal of the comparator COMP2 is connected with a buffer BUFF2, and the output terminal of the buffer BUFF2 is sequentially connected with an inverter INV2 and an inverter INV 3; the output end signal of the buffer BUFF2 and the output signal of the inverter INV2 are respectively used for feedback control of the switches S3 and S4;
the output ends of the inverter INV1 and the inverter INV3 are simultaneously connected to the input end of the xor gate NOR1, the output end of the xor gate is sequentially connected to the inverter INV4 and the inverter INV5, and the output of the inverter INV5 is a fault flag signal.
Preferably, as shown in fig. 4, the fault comparison circuit further includes resistors R1, R2, R3, R4, R5, capacitors C1, C2, C3, C4, and C5,
the resistor R1 is connected between the feedback voltage Vsense and the positive terminal of the comparator COMP1, the resistor C1 is connected between the positive terminal of the comparator COMP1 and the ground, and the resistor R1 and the capacitor C1 form an RC filter circuit for filtering interference on the feedback voltage Vsense;
the resistor R2 is connected between the first comparison voltage signal and the switch S1, the C2 is connected between the first comparison voltage signal and the common end of the switch S1 to the ground, and the resistor R2 and the capacitor C2 form an RC filter circuit for filtering interference on the first comparison voltage signal;
the resistor R3 is connected between the first comparison voltage signal and the switch S2, the C2 is connected between the first comparison voltage signal and the common end of the switch S2 to the ground, and the resistor R3 and the capacitor C2 form an RC filter circuit for filtering interference on the second comparison voltage signal;
the resistor R4 is connected between the first comparison voltage signal and the switch S3, the C3 is connected between the first comparison voltage signal and the common end of the switch S3 to the ground, and the resistor R4 and the capacitor C3 form an RC filter circuit for filtering interference on the third comparison voltage signal;
the resistor R5 is connected between the first comparison voltage signal and the switch S4, the C4 is connected between the first comparison voltage signal and the common end of the switch S4 to the ground, and the resistor R5 and the capacitor C4 form an RC filter circuit for filtering interference on the fourth comparison voltage signal.
As shown in fig. 5, the DC-DC feedback network includes an inductor L2, resistors R21 and R22, one end of the inductor L2 is connected to the output voltage signal of the DC-DC, the other end is connected to the resistor R21, the resistor R21 and the resistor R22 are connected in series to ground, and the voltage division point between the resistor R21 and the resistor R22 is fed back to the fault comparison circuit as the feedback voltage Vsense signal.
The feedback voltage Vsense passes through the filter networks R1 and C1 and acts as a positive terminal for COMP1 and COMP 2. During the rising process of the feedback voltage Vsense, initially S1 is low level, S2 is high level, the switch S2 is closed, the feedback voltage Vsense is compared with V0P75 of the reference circuit, when the feedback voltage Vsense exceeds V0P75 and does not reach V0P88, the output signal S2 is changed from high to low, and because the feedback voltage Vsense is lower than V0P88, the output signal S5 of the COMP2 comparator is low, at this time, the output of Power Good is high, namely, the Power supply has no fault. When the feedback voltage Vsense continues to rise, the signal S5 goes from low to high and the Power Good output goes from high to low once V0P88 is exceeded, i.e., a Power failure. During the descending process of the feedback voltage Vsense, a hysteresis of 30mV exists between the feedback voltage Vsense threshold value which enables the Power Good to overturn and the ascending process of the feedback voltage Vsense, the initial S3 and S5 are high level, the S2 is low level, the output of the Power Good is low, as the feedback voltage Vsense continuously descends, after the feedback voltage Vsense is lower than V0P85, the S5 level is changed from high to low, the output of the Power Good is high at the moment, namely, the Power supply has no fault, when the feedback voltage Vsense continuously descends to be lower than V0P72, the S2 is changed from low to high, and the output of the Power Good is changed from high to low, namely, the Power supply fault exists. Namely, the power failure point of the feedback voltage Vsense during rising is lower than 0.75V or higher than 0.88V, the hysteresis voltage of 30mV exists in the feedback voltage Vsense during falling, and the power failure point is lower than 0.72V or higher than 0.85V.
Because the DC-DC is a power supply module of the whole system, under the conditions of a full temperature zone, a full power supply voltage range and large external noise interference, stable power failure indication can be still kept so as to facilitate data processing of a subsequent circuit. The comparison voltage used by the invention is a voltage signal which is output by the reference circuit, has nothing to do with the temperature and the power supply voltage, and is processed by RC filtering.
Fig. 6 is a cascade configuration of the circuit of the present invention in system application, in which the Power Good Port (PWRGD) of the first circuit is connected to the enable EN port of the next-stage circuit, and when the first circuit outputs a stable output and outputs a high Power Good signal, the next-stage circuit cancels the enable state, thereby completing the setting of the Power-on sequence.
The invention is not described in detail and is within the knowledge of a person skilled in the art.
Claims (7)
1. A power failure indication circuit for DC-DC applications, comprising: including reference circuit, DC-DC feedback network, trouble comparator circuit, wherein:
the DC-DC feedback network receives the output voltage of the DC-DC, obtains a feedback voltage Vsense through resistance voltage division, and sends the feedback voltage Vsense to a fault comparison voltage;
the fault comparator comprises a reference circuit, a fault comparison circuit and a control circuit, wherein the reference circuit generates reference voltage under the action of DC-DC power supply voltage, and obtains four comparison voltage signals through resistance voltage division of the reference voltage and sends the four comparison voltage signals to the fault comparison circuit, and the four comparison voltage signals are sequentially marked as a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal from small to large;
the fault comparison circuit is used for comparing the feedback voltage Vsense value with a first comparison voltage signal, a second comparison voltage signal, a third comparison voltage signal and a fourth comparison voltage signal respectively, wherein the voltage of the feedback voltage Vsense is lower than the second comparison voltage or higher than the fourth comparison voltage in the rising process, and outputting an 'effective' fault mark signal to indicate that the power supply has a fault, otherwise, outputting an 'ineffective' fault mark signal to indicate that the power supply does not have the fault; when the voltage of the feedback voltage Vsense is lower than the first comparison voltage or higher than the third comparison voltage in the falling process, outputting an effective fault mark signal to indicate that the DC-DC power supply has a fault; otherwise, outputting an 'invalid' fault flag signal to indicate that the DC-DC power supply has no fault;
the reference circuit comprises a PMOS (P-channel metal oxide semiconductor) tube MP1, an operational amplifier OPA (operational amplifier), NPN (negative-positive-negative) triodes Q1 and Q2, resistors R11, R12, R13 and R14 and a voltage dividing resistor string, wherein the source electrode of the PMOS tube MP1 is connected with a power supply VDD, the grid electrode of the PMOS tube MP1 is connected with bias voltage Vbias, and the drain electrode of the PMOS tube MP1The voltage dividing resistor string and the drain voltage of the PMOS transistor MP1 are used as a reference power supply VBGThe electric groups R11 and R12 are commonly connected to a reference power supply VBGThe other end of the operational amplifier is connected with the same-direction end and the reverse-direction end of the OPA respectively, the emitting electrodes of the triodes Q1 and Q2 are connected with the same-direction end and the reverse-direction end of the OPA respectively, the base electrodes are connected with the voltage dividing resistor string, the collector electrode of Q2 is connected with the resistor R13, the collector electrode of Q13 is connected with the collector electrode of Q1 and one end of R14, the other end of R14 is connected with the ground, and the first comparison voltage, the second comparison voltage, the third comparison voltage and the fourth comparison voltage are respectively formed byREFThe voltage is obtained by voltage division through the voltage division resistor string.
2. A power failure indication circuit for DC-DC application as defined in claim 1, wherein: the voltage dividing resistor string is resistors which are connected in series.
3. A power failure indication circuit for DC-DC application as defined in claim 1, wherein: and a fixed voltage difference exists between the first comparison voltage signal and the second comparison voltage signal and between the third comparison voltage signal and the fourth comparison voltage signal, the fixed voltage difference is called as a hysteresis voltage, and the hysteresis voltage takes 3% -5% of the feedback voltage Vsense.
4. A power failure indication circuit for DC-DC application as defined in claim 1, wherein: the fault comparison circuit comprises switches S1, S2, S3 and S4, comparators COMP1 and COMP2, buffers BUFF1 and BUFF2, inverters INV1, INV2, INV3, INV4 and INV5 and an exclusive-OR gate NOR 1;
the feedback voltage Vsense is simultaneously connected with the positive terminals of comparators COMP1 and COMP2, the first comparison voltage signal and the second comparison voltage signal are respectively connected with the negative terminal of a comparator COMP1 through switches S1 and S2, the output terminal of the comparator COMP1 is connected with a buffer BUFF1, and the output terminal of the buffer BUFF1 is connected with an inverter INV 1; the output end signal of the buffer BUFF1 and the output signal of the inverter INV1 are respectively used for feedback control of the switches S1 and S2;
the third comparison voltage signal and the fourth comparison voltage signal are respectively connected to the negative terminal of a comparator COMP2 through switches S3 and S4, the output terminal of the comparator COMP2 is connected with a buffer BUFF2, and the output terminal of the buffer BUFF2 is sequentially connected with an inverter INV2 and an inverter INV 3; the output end signal of the buffer BUFF2 and the output signal of the inverter INV2 are respectively used for feedback control of the switches S3 and S4;
the output ends of the inverter INV1 and the inverter INV3 are simultaneously connected to the input end of the xor gate NOR1, the output end of the xor gate is sequentially connected to the inverter INV4 and the inverter INV5, and the output of the inverter INV5 is a fault flag signal.
5. A power failure indication circuit for DC-DC application as defined in claim 1, wherein: the fault comparison circuit also comprises resistors R1, R2, R3, R4 and R5, capacitors C1, C2, C3, C4 and C5,
the resistor R1 is connected between the feedback voltage Vsense and the positive terminal of the comparator COMP1, the resistor C1 is connected between the positive terminal of the comparator COMP1 and the ground, and the resistor R1 and the capacitor C1 form an RC filter circuit for filtering interference on the feedback voltage Vsense;
the resistor R2 is connected between the first comparison voltage signal and the switch S1, the C2 is connected between the first comparison voltage signal and the common end of the switch S1 to the ground, and the resistor R2 and the capacitor C2 form an RC filter circuit for filtering interference on the first comparison voltage signal;
the resistor R3 is connected between the first comparison voltage signal and the switch S2, the C2 is connected between the first comparison voltage signal and the common end of the switch S2 to the ground, and the resistor R3 and the capacitor C2 form an RC filter circuit for filtering interference on the second comparison voltage signal;
the resistor R4 is connected between the first comparison voltage signal and the switch S3, the C3 is connected between the first comparison voltage signal and the common end of the switch S3 to the ground, and the resistor R4 and the capacitor C3 form an RC filter circuit for filtering interference on the third comparison voltage signal;
the resistor R5 is connected between the first comparison voltage signal and the switch S4, the C4 is connected between the first comparison voltage signal and the common end of the switch S4 to the ground, and the resistor R5 and the capacitor C4 form an RC filter circuit for filtering interference on the fourth comparison voltage signal.
6. A power failure indication circuit for DC-DC application as defined in claim 1, wherein: the DC-DC feedback network comprises an inductor L2, resistors R21 and R22, one end of the inductor L2 is connected with an output voltage signal of the DC-DC, the other end of the inductor L2 is connected with a resistor R21, a resistor R21 and a resistor R22 are connected in series and grounded, and a voltage division point between the resistor R21 and the resistor R22 is fed back to the fault comparison circuit to serve as a feedback voltage Vsense.
7. A power failure indication circuit for DC-DC application as defined in claim 1, wherein: the DC-DC is a boost type switching power supply, a buck type switching power supply or a boost type switching power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811102946.3A CN109358295B (en) | 2018-09-20 | 2018-09-20 | Power failure indicating circuit applied to DC-DC |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811102946.3A CN109358295B (en) | 2018-09-20 | 2018-09-20 | Power failure indicating circuit applied to DC-DC |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109358295A CN109358295A (en) | 2019-02-19 |
| CN109358295B true CN109358295B (en) | 2021-06-08 |
Family
ID=65351116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811102946.3A Active CN109358295B (en) | 2018-09-20 | 2018-09-20 | Power failure indicating circuit applied to DC-DC |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109358295B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414341A (en) * | 2013-08-21 | 2013-11-27 | 电子科技大学 | Loop circuit compensating circuit used for Buck converter |
| CN205749843U (en) * | 2016-01-26 | 2016-11-30 | 深圳市瀚强科技股份有限公司 | A kind of Switching Power Supply observation circuit |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005122277A (en) * | 2003-10-14 | 2005-05-12 | Denso Corp | Band gap constant voltage circuit |
| CN102033566B (en) * | 2009-09-24 | 2013-10-23 | 上海华虹Nec电子有限公司 | Bipolar NPN type band-gap reference voltage circuit |
| CN102055341B (en) * | 2009-10-29 | 2014-02-05 | Bcd半导体制造有限公司 | Control circuit of switching power supply and switching power supply |
| CN103022965A (en) * | 2012-12-20 | 2013-04-03 | 安徽巨一自动化装备有限公司 | Monitoring circuit of 12V voltage in electric vehicle electric drive controller |
| CN103929046B (en) * | 2014-04-24 | 2016-03-30 | 东南大学 | Switching tube failure detector circuit in a kind of BUCK Topology Switch power supply |
| CN104332958B (en) * | 2014-10-30 | 2018-02-09 | 华为技术有限公司 | A kind of overvoltage crowbar and method |
| CN204721221U (en) * | 2015-06-30 | 2015-10-21 | 郝会清 | The control circuit of DC/DC switch power source output voltage |
-
2018
- 2018-09-20 CN CN201811102946.3A patent/CN109358295B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414341A (en) * | 2013-08-21 | 2013-11-27 | 电子科技大学 | Loop circuit compensating circuit used for Buck converter |
| CN205749843U (en) * | 2016-01-26 | 2016-11-30 | 深圳市瀚强科技股份有限公司 | A kind of Switching Power Supply observation circuit |
Non-Patent Citations (1)
| Title |
|---|
| 《4-bit Flash Analog to Digital Converter design using CMOS-LTE Comparator》;Meghana Kulkarni等;《2010 IEEE Asia Pacific Conference on Circuits and Systems》;20101009;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109358295A (en) | 2019-02-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20230074005A1 (en) | Temperature measurement circuit | |
| JP2009291057A (en) | Current detection circuit and switching regulator with the current detection circuit | |
| CN106571803B (en) | Over-voltage and under-voltage detection circuit | |
| TWI411903B (en) | Low drop out voltage regulator | |
| JP6292859B2 (en) | Voltage regulator | |
| CN108508953B (en) | Novel slew rate enhancement circuit and low dropout regulator | |
| CN104779793B (en) | Breakover time generation circuit for BUCK converter | |
| JP3863508B2 (en) | Power supply voltage detection circuit and semiconductor integrated circuit device | |
| TWI672572B (en) | Voltage Regulator | |
| CN115599152A (en) | Multiple LDO output voltage circuit with overshoot suppression and adaptive compensation | |
| CN110888484A (en) | Linear voltage regulator with low standby power consumption and high power supply rejection ratio | |
| US20090224804A1 (en) | Detecting circuit and electronic apparatus using detecting circuit | |
| JP2008083831A (en) | Series regulator circuit | |
| CN109358295B (en) | Power failure indicating circuit applied to DC-DC | |
| CN110858081A (en) | Simple and effective transient enhancement type LDO circuit | |
| CN115529029A (en) | Voltage comparator circuit | |
| US7122996B1 (en) | Voltage regulator circuit | |
| CN114793060A (en) | Linear voltage regulator and power management chip | |
| CN217880113U (en) | Multiple LDO output voltage circuit with overshoot suppression and adaptive compensation | |
| JP5767855B2 (en) | Regulator circuit | |
| CN114977094A (en) | Undervoltage protection circuit and electronic equipment | |
| CN108776501B (en) | Multiplexing circuit of LDO and POR | |
| CN112558680A (en) | Linear regulator and control circuit thereof | |
| CN112527044A (en) | Transient response enhancement circuit of no-capacitor LDO | |
| TW202213020A (en) | RC oscillator circuit and information processing device enable other circuit units in chip, according to clock signal, to work normally without the influence of the working temperature and/or the ambient temperature |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |