Power interruption protection circuit, power interruption protection circuit control method, power interruption protection controller, and data storage device

Abstract

To provide a power shutdown protection circuit that is robust against an overcurrent.SOLUTION: A switching power supply 110A steps up a bus voltage VBUS of an output line 108 to charge a backup capacitor 102 in a step-up mode, and steps down a voltage VSTR of the backup capacitor 102 and supplies the resultant to an output line 108 in a step-down mode. An electron fuse circuit 220 is provided between an input line 104 and the output line 108, can electrically switch between an ON state and an OFF state, and has a current clamp function in the ON state. A UVLO circuit 230 asserts an undervoltage lockout signal UVLO when the bus voltage VBUS of the output line 108 becomes less than a threshold VUVLO. A control logic 240A, in response to the assertion of the undervoltage lockout signal UVLO, sets the electron fuse circuit 220 to the OFF state and switches the switching power supply 110A to the step-down mode.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a power interruption protection circuit. [Background technology]

[0002] A stable supply of power supply voltage is essential for electronic components. If the power supply voltage for storage devices such as solid-state drives and hard disks is momentarily interrupted, there is a risk of data corruption or loss. Even after the input voltage is interrupted, it is necessary to maintain the power supply voltage for a period of time during which the load performs necessary protection processes such as data evacuation. This function is called power interruption protection, PLP (Power Loss Protection), PLI (Power Loss Imminent), or PFP (Power Failure Protection).

[0003] 1 is a block diagram of a system with a PLP function. The system 2 includes a main power supply 10, a load 20, and a power interruption protection circuit 30. The main power supply 10 receives an input voltage V of about 12 V. IN The load 20 includes a PMIC (power management circuit) 22 and a plurality of electronic components 24_1 to 24_n. The PMIC 22 generates a 12V power supply voltage V DD The power supply circuit 24_1 receives the power from the power source 24, boosts or lowers the voltage of the power supply, and supplies the power supply to the electronic components 24_1 to 24_n.

[0004] The power interruption protection circuit 30 is provided between the main power supply 10 and the load 20. The power interruption protection circuit 30 includes a switch 32, a backup capacitor , and a step-up / step-down bidirectional DC / DC converter .

[0005] The switch 32, also called an electronic fuse, is provided on the power supply line 38 connecting the main power supply 10 and the load 20. IN is supplied, switch 32 is on, and the input voltage V IN is the power supply voltage V DDThe DC / DC converter 36 has an input terminal IN connected to a power supply line 38 and an output terminal OUT connected to the backup capacitor 34. The DC / DC converter 36 converts the input voltage V IN While the input voltage V IN is boosted and the backup capacitor 34 is charged. The capacitance of the backup capacitor 34 is C, and the voltage generated in the backup capacitor 34 is V STR Then, the charge Q and energy E stored in the backup capacitor 34 are expressed by the following equations: Q=C·V STR E is E=C·V STR 2 / 2

[0006] The power cutoff protection circuit 30 is IN When the interruption (loss) of the power supply is detected, the switch 32 is turned off. Then, the DC / DC converter 36 operates in the reverse direction as a step-down converter with the OUT side as the input and the IN side as the output, and the capacitor voltage V STR , the power supply voltage V DD and supplies it to the load 20. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-5924 Summary of the Invention [Problem to be solved by the invention]

[0008] The cause of power loss to load 20 is the input voltage V IN In addition to the loss / reduction of power, a ground fault at the input terminal, and an increase in input voltage, there is also an increase in the current of the load 20. In other words, if the load current becomes excessive and there is a shortage of power from the main power supply 10, the power supply voltage V DD decreases.

[0009] The present disclosure has been made in view of the above-mentioned problems, and one exemplary purpose of an embodiment thereof is to provide a power supply interruption protection circuit that is robust against overcurrent. [Means for solving the problem]

[0010] A power interruption protection circuit according to one embodiment of the present disclosure includes an input line for receiving an input voltage, an output line to be connected to a load, a backup capacitor, a switching power supply that is switchable between a step-up mode and a step-down mode and is connected to the output line and the backup capacitor, and that, in the step-up mode, steps up the bus voltage of the output line to charge the backup capacitor, and, in the step-down mode, steps down the voltage of the backup capacitor and supplies it to the output line, an electronic fuse circuit that is provided between the input line and the output line and is electrically switchable between an on state and an off state and has a current clamping function in the on state, an undervoltage lockout circuit that asserts an undervoltage lockout signal when the bus voltage of the output line falls below a threshold, and control logic that, when the undervoltage lockout signal is asserted, turns off the electronic fuse circuit and switches the switching power supply to the step-down mode.

[0011] Another aspect of the present disclosure is a power interruption protection controller including: an input pin for receiving an input voltage, an output pin for connecting to a load, a capacitor connection pin for connecting a backup capacitor, at least one switching pin for connecting to the output pin via an external inductor, a converter block switchable between a step-up mode and a step-down mode, connected to the at least one switching pin, the output pin, and the capacitor connection pin, and stabilizing the voltage of the backup capacitor at a first target level in the step-up mode and stabilizing the voltage of the output pin at a second target level in the step-down mode, an electronic fuse circuit provided on a power supply line connecting the input pin and the output pin, electrically switchable between an ON state and an OFF state and having a current clamp function in the ON state, an undervoltage lockout circuit for asserting an undervoltage lockout signal when the voltage of the output pin falls below a threshold, and control logic for turning off the electronic fuse circuit and switching the converter block to the step-down mode when the undervoltage lockout signal is asserted.

[0012] Any combination of the above elements, or mutual substitution of elements or expressions between methods, devices, systems, etc., are also valid aspects of the present invention or the present disclosure. Furthermore, the description in this section (Means for Solving the Problems) does not explain all essential features of the present invention, and therefore, subcombinations of the described features may also constitute the present invention. [Effects of the Invention]

[0013] According to an aspect of the present disclosure, it is possible to provide a robust power interruption protection function even against overcurrent. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram of a system with PLP functionality. [Figure 2]FIG. 2 is a block diagram of a system including the power interruption protection circuit according to the first embodiment. [Figure 3] FIG. 3 is an operational waveform diagram of the power cutoff protection circuit of FIG. [Figure 4] FIG. 4 is an operational waveform diagram of the comparative technique. [Figure 5] FIG. 5 is a circuit diagram of an example of the configuration of an electronic fuse and an overcurrent detection circuit. [Figure 6] FIG. 6 is a block diagram of a system including a power interruption protection circuit according to the second embodiment. [Figure 7] FIG. 7 is an operational waveform diagram of the power cutoff protection circuit of FIG. [Figure 8] FIG. 8 is a circuit diagram of a system including a power interruption protection circuit according to the third embodiment. [Figure 9] FIG. 9 is a circuit diagram of a system including a power interruption protection circuit according to the fourth embodiment. [Figure 10] FIG. 10 is a block diagram of a data storage device with PLP functionality. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Outline of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0016] a switching power supply that is switchable between a step-up mode and a step-down mode and is connected to the output line and the backup capacitor, and that, in the step-up mode, steps up the bus voltage of the output line to charge the backup capacitor, and, in the step-down mode, steps down the voltage of the backup capacitor and supplies it to the output line; an electronic fuse circuit that is provided between the input line and the output line and is electrically switchable between an on state and an off state and has a current clamping function in the on state; an undervoltage lockout circuit that asserts an undervoltage lockout signal when the bus voltage of the output line falls below a threshold; and control logic that, when the undervoltage lockout signal is asserted, turns off the electronic fuse circuit and switches the switching power supply to the step-down mode.

[0017] In the normal operating mode (normal state), the switching power supply operates in step-up mode and stores power in the backup capacitor. In the normal operating mode, when the load current increases, the current clamp circuit of the electronic fuse circuit is activated and the current flowing through the electronic fuse circuit is clamped. As a result, the bus voltage of the output line drops. When the drop in bus voltage is detected by the undervoltage lockout circuit, the electronic fuse circuit is turned off and the switching power supply switches to step-down mode, thereby supplying the power stored in the backup capacitor to the load. This configuration can provide a robust power interruption protection function even against overcurrent.

[0018] In one embodiment, the power interruption protection circuit may further include an overcurrent detection circuit that has a threshold lower than the limit current of the electronic fuse circuit and asserts an overcurrent detection signal when the current on the input line exceeds the threshold. The assertion of the overcurrent detection signal may be transmitted to the load.

[0019] In one embodiment, the switching power supply may include a step-up / step-down bidirectional DC / DC converter that is reversible in the direction of power transmission between step-up mode and step-down mode.

[0020] In one embodiment, the power interruption protection circuit may further include a protection switch connected between the inductor of the step-up / step-down bidirectional DC / DC converter and the output line. When the backup capacitor fails in a short-circuit mode, the protection switch is turned off to continue supplying power to the load.

[0021] In one embodiment, the switching power supply may include a boost converter that is active in boost mode and has an input node connected to the output line and an output node connected to the backup capacitor, and a buck converter that is active in buck mode and boost mode and has an input node connected to the output line and an output node connected to the backup capacitor. In a configuration using a bidirectional DC / DC converter, a control delay occurs when switching the operating mode of the bidirectional DC / DC converter, which may cause a drop in power supply voltage. In contrast, in a configuration where the switching power supply includes a boost converter and a buck converter, by keeping the buck converter operating at all times, there is no need to wait for the buck converter to start up when a power loss occurs, and power stored in the backup capacitor can be quickly supplied to the load.

[0022] In one embodiment, the power interruption protection circuit may further include a protection switch connected between the inductor of each of the boost converter and the buck converter and the output line. When the backup capacitor fails in a short circuit mode, the protection switch is turned off to continue supplying power to the load.

[0023] In one embodiment, the load may be a solid state drive (SSD).

[0024] A data storage device according to an embodiment may include any of the power cutoff protection circuits described above.

[0025] a converter block that is switchable between a step-up mode and a step-down mode, is connected to the at least one switching pin, the output pin, and the capacitor connection pin, and that stabilizes the voltage of the backup capacitor at a first target level in the step-up mode and stabilizes the voltage of the output pin at a second target level in the step-down mode; an electronic fuse circuit that is provided on a power supply line connecting the input pin and the output pin, is electrically switchable between an on state and an off state, and has a current clamping function in the on state; an undervoltage lockout circuit that asserts an undervoltage lockout signal when the voltage of the output pin falls below a threshold; and control logic that, when the undervoltage lockout signal is asserted, turns off the electronic fuse circuit and switches the converter block to the step-down mode.

[0026] In one embodiment, the power interruption protection controller may further include an overcurrent detection circuit that has a threshold lower than the limit current of the electronic fuse circuit and asserts an overcurrent detection signal when the current in the power line exceeds the threshold. The assertion of the overcurrent detection signal may be transmitted to the load.

[0027] In one embodiment, the converter block may include a step-up / step-down bidirectional DC / DC converter that is reversible in the direction of power transmission between step-up mode and step-down mode.

[0028] In one embodiment, the converter block may include a boost converter that is active in boost mode and has the capacitor connection pin as its output, and a buck converter that is active in boost mode and buck mode and has the capacitor connection pin as its input.

[0029] In one embodiment, the power interruption protection controller may be monolithically integrated on a single semiconductor substrate. "Monolithically integrated" includes cases where all of the circuit components are formed on a semiconductor substrate or where the main circuit components are monolithically integrated, and some resistors and capacitors for adjusting circuit constants may be provided outside the semiconductor substrate. By integrating the circuit on a single chip, the circuit area can be reduced and the characteristics of the circuit elements can be maintained uniformly.

[0030] In one embodiment, the load may be a solid state drive (SSD).

[0031] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. Furthermore, the embodiments are merely examples and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0032] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected, but also a case in which component A and component B are indirectly connected via another component that does not affect the electrical connection or impair function. Also, "a state in which component C is provided between component A and component B" includes not only a case in which component A and component C, or component B and component C, are directly connected, but also a case in which component C is indirectly connected via another component that does not affect the electrical connection or impair function.

[0033] (Embodiment 1) 2 is a block diagram of a system 2A including a power interruption protection circuit 100A according to the first embodiment. The system 2A includes a main power supply 10, a load 20, and a power interruption protection circuit 100A. The main power supply 10 is, for example, an AC / DC converter or a USB (Universal Serial Bus) bus, and receives a DC input voltage V at a predetermined first voltage level (hereinafter, 12 V). IN is supplied to the power cutoff protection circuit 100A.

[0034] The power cutoff protection circuit 100A operates when the input voltage V IN The bus voltage V BUS supply.

[0035] The power cutoff protection circuit 100A includes an input line 104, an output line 108, an electronic fuse circuit 220, a backup capacitor 102, a switching power supply 110A, a UVLO (undervoltage lockout) circuit 230, control logic 240A, and an overcurrent detection circuit 250.

[0036] The main power supply 10 and the load 20 are connected by a bus line. An electronic fuse circuit 220 is provided on the bus line. The bus line is referred to as an input line 104 on the main power supply 10 side from the electronic fuse circuit 220, and as an output line 108 on the load 20 side from the electronic fuse circuit 220. An input voltage V IN A load 20 is connected to the output line 108.

[0037] The electronic fuse circuit 220 is provided between the input line 104 and the output line 108, and can be electrically switched between an ON state and an OFF state. The electronic fuse circuit 220 has a current clamping function (current limiting function), and in the ON state, the current I IN is the predetermined limit current I LIM Limit it so that it does not exceed (I IN LIM ).

[0038] ​The backup capacitor 102 is connected to a backup line 106 .

[0039] The switching power supply 110A is connected to the output line 108 and the backup capacitor 102. The switching power supply 110A can switch between a step-up mode and a step-down mode, and in the step-up mode, the bus voltage V BUS is boosted and charged to the backup capacitor 102. By this charging, the voltage V STR is regulated to a predetermined voltage level.

[0040] In the step-down mode, the switching power supply 110A reduces the voltage V of the backup capacitor 102. STR and supplies it to the output line 108. In this embodiment, the switching power supply 110A is a step-up / step-down bidirectional DC / DC converter, and the direction of power transmission can be reversed between the step-up mode and the step-down mode.

[0041] The UVLO circuit 230 is configured to detect the bus voltage V BUS is a predetermined threshold V UVLO If the voltage drops below this, the undervoltage lockout signal UVLO is asserted.

[0042] The control logic 240A comprehensively controls the PLP controller 200A. Specifically, the control logic 240A controls the on / off of the electronic fuse circuit 220 and also controls the operation mode of the converter block 210A.

[0043] When the UVLO signal is asserted, the control logic 240A turns off the electronic fuse circuit 220 and switches the switching power supply 110A to the step-down mode.

[0044] The overcurrent detection circuit 250 detects the limit current I of the electronic fuse circuit 220. LIM Lower Threshold I OCP and the bus current IBUS is the threshold I OCP , the control logic 240A asserts the overcurrent detection signal OCD. When the OCD signal is asserted, the control logic 240A notifies the load 20. In this embodiment, the overcurrent detection signal OCD does not affect the control of the electronic fuse circuit 220 or the switching power supply 110A.

[0045] Some of the components of the power interruption protection circuit 100A are integrated into a power interruption protection controller (hereinafter referred to as PLP controller) 200A. Specifically, the PLP controller 200A is a functional IC (Integrated Circuit) that includes a converter block 210A, an electronic fuse circuit 220, a UVLO circuit 230, a control logic 240A, and an overcurrent detection circuit 250, and is integrated onto a single semiconductor substrate.

[0046] The PLP controller 200A includes an input pin VIN, an output pin VBUS, a switching pin LX, a capacitor connection pin STR, and feedback pins FB1 and FB2. The input pin VIN is connected to the main power supply 10, and the input voltage V IN A load 20 is connected to the output pin VBUS. An electronic fuse circuit 220 is connected between the input pin VIN and the output pin VBUS.

[0047] The switching power supply 110A includes a converter block 210A, an inductor L1, and a capacitor C1. The capacitor C1 is connected to the output line 108. The switching pin LX is connected to the output line 108 via the external inductor L1.

[0048] The converter block 210A includes a high-side transistor M1, a low-side transistor M2, and a feedback controller 212. The feedback controller 212 outputs the voltage V of the backup capacitor 102 via a feedback pin FB1. STR Feedback voltage V according to FB1 The feedback voltage V FB1 is the voltage V STRIt may be a voltage obtained by dividing the voltage.

[0049] In boost mode, the feedback controller 212 controls the feedback voltage V FB1 The high-side transistor M1 and the low-side transistor M2 are driven so that the

[0050] The feedback controller 212 receives the bus voltage V on the output line 108 via the feedback pin FB2. BUS Feedback voltage V according to FB2 The feedback voltage V FB2 is the bus voltage V BUS It may be a voltage obtained by dividing the voltage.

[0051] In the buck mode, the feedback controller 212 controls the feedback voltage V FB2 The high-side transistor M1 and the low-side transistor M2 are driven so that the

[0052] The above is the configuration of the power cutoff protection circuit 100A. Next, the operation of the power cutoff protection circuit 100A will be described.

[0053] 3 is an operation waveform diagram of the power cutoff protection circuit 100A of FIG. 2. Before time t0, the period is a normal operation period, and the control logic 240A turns on the electronic fuse circuit 220 and sets the switching power supply 110A to the boost mode. The switching power supply 110A in the boost mode reduces the voltage V of the backup capacitor 102. STR is stabilized to the target level, and the backup capacitor 102 stores the energy E=1 / 2×C·V STR 2 During normal operation, the load current I OUT and the input current I IN are equal.

[0054] At time t0, the load current I OUT increases. The load current I OUT As the input current IIN At time t1, the input current I IN is the threshold value I of the overcurrent detection circuit 250. OCP The control logic 240A does not use the assertion of the OCD signal to control the electronic fuse circuit 220 or the switching power supply 110A.

[0055] The electronic fuse circuit 220 reduces the input current I IN is the limit current I LIM Then, I OUT > IN As a result, the capacitor C1 is discharged, and the bus voltage V BUS decreases over time.

[0056] At time t2, the bus voltage V BUS is the threshold voltage V of the UVLO circuit 230. UVLO When the input voltage Vcc is lower than the reference voltage Vcc, the UVLO signal is asserted. In response to the assertion of the UVLO signal, the control logic 240A turns off the electronic fuse circuit 220. This reduces the input current I IN In response to the assertion of the UVLO signal, the control logic 240A switches the switching power supply 110A to the step-down mode. This causes the load current I OUT as the backup current I STR The voltage V of the backup capacitor 102 is supplied. STR decreases over time.

[0057] The above is the operation of the power cutoff protection circuit 100A.

[0058] This power cutoff protection circuit 100A can provide a robust power cutoff protection function even against overcurrent.

[0059] The advantages of the power interruption protection circuit 100A become clear when compared with the comparative technology. Figure 4 is an operational waveform diagram of the comparative technology. In the comparative technology, in response to the assertion of the OCD signal at time t1, the electronic fuse circuit 220 is turned off and the switching power supply 110A switches to the step-down mode. In other words, in the comparative technology, when an overcurrent occurs, the power supply is immediately switched from the main power supply 10 to the backup capacitor 102.

[0060] Returning to the power cutoff protection circuit 100A, the load 20 is in an overcurrent state (I IN >I OCP ), the electronic fuse circuit 220 is not immediately turned off, but is maintained in a normal operating state and the limit current I LIM Current limited to I IN is supplied from the main power supply 10 to the load 20. And, the bus voltage V BUS is the threshold V UVLO When the bus voltage V drops to , the power supply is switched from the main power supply 10 to the backup capacitor 102. In other words, compared to the comparative technology, the period during which the main power supply 10 can be used is extended by the length of t1 to t2 in FIG. 3, but in exchange, the start of the release of energy from the backup capacitor 102 can be delayed. BUS This can delay the decrease in the load current, thereby extending the period during which the load 20 can operate.

[0061] 5 is a circuit diagram of a configuration example of the electronic fuse circuit 220 and the overcurrent detection circuit 250. The electronic fuse circuit 220 includes transistors M11 to M15, a resistor R11, an external resistor R12, an operational amplifier 222, a voltage source 224, an operational amplifier 226, and a gate driver 228. The transistors M11 and M12 are switches that switch on and off between the input pin VIN and the output pin.

[0062] The transistors M13 and M14 are replicas of the transistors M11 and M12, and are used to control the current I INThe gates of the transistors M11 to M14 are connected in common. The transistor M15 is connected to the transistor M14. The operational amplifier 222 receives the voltage at one end of the transistor M14 and the voltage at the corresponding end of the transistor M12 (i.e., the output pin VBUS). The output of the operational amplifier 222 is connected to the gate of the transistor M15. The operational amplifier 222 applies feedback so that the voltage at one end of the transistor M14 becomes equal to the voltage at the corresponding end of the transistor M12, that is, so that the voltage across the transistors M11 and M12 becomes equal to the voltage across the transistors M13 and M14. At this time, the input current I IN The detected current I is proportional to CS is playing.

[0063] Resistors R11 and R12 are connected between the drain of the transistor M15 and ground. For example, the PLP controller 200A may include a current sense pin CS, and the resistor R12 may be externally connected to the current sense pin CS. The resistor R12 has a resistor R11 connected to the drain of the transistor M15 and a resistor R12 connected to the current sense pin CS. CS A voltage drop V proportional to CS occurs.

[0064] The voltage source 224 limits the current I LIM The reference voltage V LIM For example, the voltage source 224 generates a limit current I LIM The voltage source 224 may be a constant voltage source.

[0065] The operational amplifier 226 outputs the current sense signal V CS and the reference voltage V LIM voltage V ERR The gate driver 228 generates a high gate voltage V to the gates of the transistors M11 and M12 during the period when the electronic fuse circuit 220 is to be turned on. GThe gate driver 228 may have a soft start (SS) function to prevent inrush current. The gate driver 228 with soft start applies a gate voltage V G is gradually changed to cause a gradual transition from the OFF state to the ON state.

[0066] The gate driver 228 is V CS <V LIM In this state, the error voltage V ERR Depending on the gate voltage V G This increases the resistance of the transistors M11 and M12, and the input current I IN This feedback reduces the input current I IN is the limit current I LIM is clamped so as not to exceed

[0067] The overcurrent detection circuit 250 includes a voltage source 252 and a comparator 254. The voltage source 252 outputs an overcurrent threshold I OCP The threshold voltage V OCP For example, the voltage source 252 generates an overcurrent threshold I OCP The voltage source 252 may be a constant voltage source. The comparator 254 receives the current detection signal V CS is the threshold voltage V OCP Compared to V CS >V OCP When this happens, the OCD signal goes high (asserted).

[0068] The configurations of the electronic fuse circuit 220 and the overcurrent detection circuit 250 are not limited to those shown in Fig. 5. For example, the transistors M11 to M14 of the electronic fuse circuit 220 may be PMOS transistors.

[0069] The current detection method is not limited to the combination of replica transistors and resistors. For example, a sense resistor may be inserted in series with the transistors M11 and M12 that make up the switch, and current clamping or overcurrent detection may be performed based on the voltage drop across the sense resistor.

[0070] Alternatively, the current may be detected based on the potential difference between the VIN terminal and the VBUS terminal, that is, the voltage across the transistors M11 and M12, and current clamping or overcurrent control may be performed based on the detected current.

[0071] (Embodiment 2) 6 is a block diagram of a system 2B including a power cutoff protection circuit 100B according to embodiment 2. In the power cutoff protection circuit 100B of FIG. 6, the configuration of a switching power supply 110B is different from that of the switching power supply 110A of FIG.

[0072] The switching power supply 110B includes a step-down converter 112 and a step-up converter 114. The PLP controller 200B has two switching pins LX1 and LX2 and two feedback pins FB1 and FB2. The switching pin LX1 is connected to an inductor L1, and the switching pin LX2 is connected to an inductor L2. The feedback pin FB1 is connected to an output voltage V 1 supplied to the load 20. BUS Feedback voltage V according to FB1 The feedback pin FB2 receives the voltage V generated in the backup capacitor 102. STR Feedback voltage V according to FB2 is fed back.

[0073] The buck converter 112 is active in both the boost mode and the buck mode, and has an input node connected to the backup capacitor 102 and an output node connected to the output line 108. The buck converter 112 includes a high-side transistor M1, a low-side transistor M2, and a feedback controller 214. The feedback controller 214 controls the bus voltage V supplied to the load 20.BUS Feedback voltage V according to FB2 The bus voltage V BUS The target level is V REF(BUCK) The high-side transistor M1 and the low-side transistor M2 are driven so that the voltage approaches

[0074] Preferably, the target voltage V of the output voltage of the buck converter 112 REF(BUCK) is the input voltage V IN It is preferable to set the voltage lower than the normal voltage level (for example, 12 V) of the load 20. MIN It is better to set it lower than V REF(BUCK) <V MIN

[0075] For example, the target voltage V REF(BUCK) is set to 8V. In this embodiment, the buck converter 112 only has current source capability and does not have current sink capability. Therefore, the bus voltage V BUS is the target voltage V REF(BUCK) In the higher state, the buck converter 112 is operational but operates at a voltage lower than the bus voltage V BUS will not affect the

[0076] The boost converter 114 is disabled in the buck mode. The boost converter 114 is enabled in the boost mode, with its input node connected to the output line 108 and its output node connected to the buck line 106. The boost converter 114 includes a high-side transistor M3, a low-side transistor M4, and a feedback controller 216. The feedback controller 216 controls the feedback voltage V FB2 , and the voltage V generated in the backup capacitor 102 STR The target level is V REF(BOOST) The boost converter 114 drives the high-side transistor M3 and the low-side transistor M4 so that the voltage Vin approaches 1. The boost converter 114 may be a diode rectification type in which the high-side transistor M3 is replaced with a diode.

[0077] The control logic 240B controls the operation mode of the converter block 210B based on the UVLO signal generated by the UVLO circuit 230. Specifically, in a normal state, the control logic 240B supplies a high enable signal EN_BOOST to the feedback controller 216 to enable the boost converter 114. When the UVLO signal is asserted, the control logic 240B changes the enable signal EN_BOOST to low, thereby disabling the boost converter 114.

[0078] The above is the configuration of the PLP controller 200B. Next, its operation will be described.

[0079] Fig. 7 is an operational waveform diagram of the power interruption protection circuit 100B in Fig. 6. Before time t0, the period is normal operation, and the control logic 240B turns on the electronic fuse circuit 220. The control logic 240B also turns the enable signal EN_BOOST for the boost converter 114 high, setting the switching power supply 110B in boost mode.

[0080] The voltage V of the backup capacitor 102 is increased by the switching power supply 110B in boost mode. STR is the target level V REF(BOOST) The backup capacitor 102 is stabilized to the energy E=1 / 2×C·V STR 2 During normal operation, the load current I OUT and the input current I IN Also, as mentioned above, the buck converter 112 is operating, but the bus voltage V BUS does not affect V BUS ≒V IN This becomes:

[0081] At time t0, the load current I OUT increases. The load current I OUT As the input current I INAt time t1, the input current I IN is the threshold value I of the overcurrent detection circuit 250. OCP The OCD signal is asserted when the voltage exceeds the threshold voltage Vcc. The control logic 240B does not use the assertion of the OCD signal to control the electronic fuse circuit 220 or the switching power supply 110B.

[0082] The electronic fuse circuit 220 reduces the input current I IN is the limit current I LIM Then, I OUT > IN As a result, the capacitor C1 is discharged, and the bus voltage V BUS decreases over time.

[0083] At time t2, the bus voltage V BUS is the threshold voltage V of the UVLO circuit 230. UVLO When the input voltage Vcc is lower than the reference voltage Vcc, the UVLO signal is asserted. In response to the assertion of the UVLO signal, the control logic 240B turns off the electronic fuse circuit 220. This reduces the input current I IN In response to the assertion of the UVLO signal, the control logic 240B switches the enable signal EN_BOOST for the boost converter 114 to low, and switches the switching power supply 110B to the buck mode. As a result, the load current I OUT as the backup current I STR The voltage V of the backup capacitor 102 is supplied. STR decreases over time.

[0084] The above is the operation of the power cutoff protection circuit 100B.

[0085] In the power supply interruption protection circuit 100A in FIG. 2, the switching power supply 110A is configured with one bidirectional DC / DC converter and is capable of switching between step-up mode and step-down mode. In this case, if the delay in switching from step-up mode to step-down mode is large, the bus voltage V BUSIn contrast, the power cutoff protection circuit 100B of FIG. 6 does not require the converter to switch from step-up operation to step-down operation, so there is no delay associated with the switching. Therefore, the bus voltage V BUS can be prevented from decreasing.

[0086] Specifically, the step-down converter 112 converts the input voltage V IN Even when the bus voltage V BUS Therefore, immediately after the electronic fuse circuit 220 turns off at time t2, the bus voltage V BUS target voltage V REF(BUCK) can be stabilized to

[0087] The boost converter 114 may be a diode rectifier type, in which case the high-side transistor M1 may be configured as a diode.

[0088] (Embodiment 3) 8 is a circuit diagram of a system 2C including a power interruption protection circuit 100C according to the third embodiment. The power interruption protection circuit 100C includes a protection switch 260 in addition to the components of the power interruption protection circuit 100A in FIG. 2. The inductor L1 is connected to the VBUS pin via the protection switch 260. That is, the inductor L1 and the VBUS pin can be electrically separated.

[0089] The protection switch 260 may be integrated into the PLP controller 200C. The PLP controller 200C further includes an inductor connection pin VB. The inductor L1 is externally connected between the VB pin and the LX pin. The protection switch 260 is connected between the VBUS pin and the VB pin.

[0090] The control logic 240C controls the protection switch 260. The control logic 240C turns on the protection switch 260 in the step-up mode and the step-down mode. For example, the control logic 240C turns off the protection switch 260 when it detects a short-circuit mode failure (a ground fault at the STR pin) of the backup capacitor 102. Furthermore, the control logic 240C may turn off the protection switch 260 when it detects a ground fault at the LX pin.

[0091] The configuration of the converter block 210C is similar to that of the converter block 210A in FIG.

[0092] According to the third embodiment, in a situation where the backup capacitor 102 fails in a short-circuit mode, the VBUS pin can be separated from the failure point, and power can be continuously supplied from the main power supply 10 to the load 20.

[0093] (Embodiment 4) 9 is a circuit diagram of a system 2D including a power interruption protection circuit 100D according to the fourth embodiment. The power interruption protection circuit 100D includes a protection switch 260 in addition to the components of the power interruption protection circuit 100B in FIG. 6. The inductors L1 and L2 are connected to the VBUS pin via the protection switch 260. That is, the inductors L1 and L2 can be electrically separated from the VBUS pin.

[0094] The protection switch 260 may be integrated into the PLP controller 200D. The PLP controller 200D further includes a VB pin. An inductor L1 is externally connected between the VB pin and the LX1 pin, and an inductor L2 is externally connected between the VB pin and the LX2 pin. The protection switch 260 is connected between the VBUS pin and the VB pin.

[0095] The control logic 240D controls the protection switch 260. The control logic 240D turns on the protection switch 260 in the step-up mode and the step-down mode. For example, the control logic 240D turns off the protection switch 260 when it detects a short-circuit mode failure (a ground fault at the STR pin) of the backup capacitor 102. Furthermore, the control logic 240D may turn off the protection switch 260 when it detects a ground fault at the LX pin.

[0096] The configuration of the converter block 210D is similar to that of the converter block 210B in FIG.

[0097] According to the fourth embodiment, in a situation where the backup capacitor 102 fails in a short-circuit mode, the VBUS pin can be separated from the failure point, and power can be continuously supplied from the main power supply 10 to the load 20.

[0098] (Application) Power interruption protection circuits 100A to 100D (hereinafter collectively referred to as 100) according to the embodiments can be used in a data storage device 300. Fig. 10 is a block diagram of a data storage device 300 with a PLP function. The data storage device 300 is, for example, an SSD (Solid State Drive), and includes a power interruption protection circuit 100, a PMIC 302, a controller 304, a NAND memory 306, a cache memory 308, and an interface 310.

[0099] The data storage device 300 may be for a server, may be built into a computer, or may be a portable SSD.

[0100] The power supply cutoff protection circuit 100 receives a DC input voltage V from an AC / DC converter or a USB bus (the above-mentioned main power supply 10, not shown in FIG. 10). DC The PMIC302 receives the power supply voltage V DD The PMIC 302 supplies power supply voltage to the controller 304, the NAND memory 306, the cache memory 308, and the interface 310.

[0101] The power cutoff protection circuit 100 is not limited to use in the data storage device 300, but can be used in any application where the power supply voltage must be maintained for a certain period of time after the power is cut off.

[0102] The embodiments are merely examples, and it will be understood by those skilled in the art that there are various variations in the combination of each component and each treatment process, and that such variations are also included within the scope of this disclosure or the present invention. [Explanation of symbols]

[0103] 2. System 10 Main power 20 Load 22 PMIC 24 Electronic Components 100 Power cutoff protection circuit 102 Backup capacitor 104 input lines 106 Backlap Line 108 output lines 110 Switching Power Supply 112 Buck Converter 114 Boost Converter 200 PLP Controller 210 Converter Block 212 Feedback Controller 220 Electronic Fuse Circuit 230 UVLO circuit 240 Control Logic 250 Overcurrent detection circuit 260 Protection Switch LX Switching Pin FB Feedback pin VIN input pin VBUS output pin VB Inductor connection pin 300 Data storage device 302 PMIC 304 Controller 306 NAND memory 308 Cache Memory 310 Interface

Claims

1. an input line to receive an input voltage; an output line to be connected to a load; a capacitor connected to the output line; A backup capacitor; a switching power supply that is switchable between a step-up mode and a step-down mode, is connected to the output line and the backup capacitor, and in the step-up mode, steps up a bus voltage of the output line to charge the backup capacitor, and in the step-down mode, steps down the voltage of the backup capacitor and supplies it to the output line; an electronic fuse circuit provided between the input line and the output line, the electronic fuse circuit being electrically switchable between an on state and an off state and having a current clamping function in the on state; an undervoltage lockout circuit that asserts an undervoltage lockout signal when the bus voltage on the output line falls below a threshold; control logic that, when the undervoltage lockout signal is asserted, turns off the electronic fuse circuit and switches the switching power supply to the step-down mode; A power cutoff protection circuit comprising:

2. an overcurrent detection circuit having a threshold lower than the limit current of the electronic fuse circuit and asserting an overcurrent detection signal when the current on the input line exceeds the threshold; 2. The power interruption protection circuit according to claim 1, wherein the assertion of the overcurrent detection signal is transmitted to the load.

3. 3. The power supply interruption protection circuit according to claim 1, wherein the switching power supply includes a step-up / step-down bidirectional DC / DC converter capable of reversing a direction of power transmission between the step-up mode and the step-down mode.

4. 4. The power interruption protection circuit according to claim 3, further comprising a protection switch connected between an inductor of the step-up / step-down bidirectional DC / DC converter and the output line.

5. The switching power supply a boost converter active in the boost mode, the boost converter having an input node connected to the output line and an output node connected to the backup capacitor; a step-down converter that is active in the step-up mode and the step-down mode, and has an input node connected to the output line and an output node connected to the backup capacitor; 3. The power supply interruption protection circuit according to claim 1, comprising:

6. 6. The power interruption protection circuit according to claim 5, further comprising a protection switch connected between the inductor of each of the step-up converter and the step-down converter and the output line.

7. 7. The power interruption protection circuit according to claim 1, wherein the load is an SSD (Solid State Drive).

8. A data storage device comprising the power interruption protection circuit according to any one of claims 1 to 7.

9. an input pin for receiving an input voltage; an output pin to be connected to a load and a capacitor; a capacitor connection pin to which a backup capacitor is to be connected; at least one switching pin to be connected to the output pin via an external inductor; a converter block that is switchable between a step-up mode and a step-down mode, that is connected to the at least one switching pin, the output pin, and the capacitor connection pin, that stabilizes the voltage of the backup capacitor at a first target level in the step-up mode, and that stabilizes the voltage of the output pin at a second target level in the step-down mode; an electronic fuse circuit that is provided on a power supply line connecting the input pin and the output pin, the electronic fuse circuit being electrically switchable between an on state and an off state and having a current clamping function in the on state; an undervoltage lockout circuit that asserts an undervoltage lockout signal when the voltage at the output pin falls below a threshold; control logic that, when the undervoltage lockout signal is asserted, turns off the electronic fuse circuit and switches the converter block to the buck mode; A power interruption protection controller comprising:

10. an overcurrent detection circuit having a threshold lower than a limit current of the electronic fuse circuit and asserting an overcurrent detection signal when the current of the electronic fuse circuit exceeds the threshold; 10. The power interruption protection controller of claim 9, further comprising: transmitting assertion of the overcurrent detection signal to the load.

11. 11. The power interruption protection controller according to claim 9, wherein the converter block includes a step-up / step-down bidirectional DC / DC converter capable of reversing a direction of power transmission between the step-up mode and the step-down mode.

12. an inductor connection pin to be connected to one end of the inductor of the step-up / step-down bidirectional DC / DC converter; a protection switch connected between the output pin and the inductor connection pin; The power interruption protection controller of claim 11 further comprising:

13. The converter block comprises: a boost converter that is active in the boost mode and has the capacitor connection pin as its output; a step-down converter that is active in the step-up mode and the step-down mode and has the capacitor connection pin as an input; 11. A power interruption protection controller according to claim 9 or 10, comprising:

14. an inductor connection pin to be connected to one end of an inductor of each of the step-up converter and the step-down converter; a protection switch connected between the output pin and the inductor connection pin; The power interruption protection controller of claim 13 further comprising:

15. 15. The power interruption protection controller according to claim 9, which is monolithically integrated on a single semiconductor substrate.

16. 16. The power interruption protection controller according to claim 9, wherein the load is a solid state drive (SSD).

17. A control method for a power cutoff protection circuit, The power supply cutoff protection circuit includes: an input line to receive an input voltage; an output line to be connected to a load; a capacitor connected to the output line; A backup capacitor; a switching power supply that is switchable between a step-up mode and a step-down mode, is connected to the output line and the backup capacitor, and in the step-up mode, steps up a bus voltage of the output line to charge the backup capacitor, and in the step-down mode, steps down the voltage of the backup capacitor and supplies it to the output line; an electronic fuse circuit disposed between the input line and the output line; Equipped with The control method includes: clamping a current flowing through the electronic fuse circuit; asserting an undervoltage lockout signal when the bus voltage on the output line falls below a threshold; when the undervoltage lockout signal is asserted, turning off the electronic fuse circuit and switching the switching power supply to the step-down mode; A control method comprising:

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