WO2023188964A1 - 発光素子駆動装置、発光制御装置、発光装置 - Google Patents

発光素子駆動装置、発光制御装置、発光装置 Download PDF

Info

Publication number
WO2023188964A1
WO2023188964A1 PCT/JP2023/005649 JP2023005649W WO2023188964A1 WO 2023188964 A1 WO2023188964 A1 WO 2023188964A1 JP 2023005649 W JP2023005649 W JP 2023005649W WO 2023188964 A1 WO2023188964 A1 WO 2023188964A1
Authority
WO
WIPO (PCT)
Prior art keywords
current
signal
light emitting
emitting element
switch
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.)
Ceased
Application number
PCT/JP2023/005649
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
啓 青木
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rohm Co Ltd
Original Assignee
Rohm Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Rohm Co Ltd filed Critical Rohm Co Ltd
Priority to DE112023001176.1T priority Critical patent/DE112023001176T5/de
Priority to JP2024511415A priority patent/JPWO2023188964A1/ja
Priority to CN202380031521.0A priority patent/CN118975406A/zh
Publication of WO2023188964A1 publication Critical patent/WO2023188964A1/ja
Priority to US18/895,569 priority patent/US20250024568A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/48—Details of LED load circuits with an active control inside an LED matrix having LEDs organised in strings and incorporating parallel shunting devices
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H05B45/14—Controlling the intensity of the light using electrical feedback from LEDs or from LED modules
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/54—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits in a series array of LEDs

Definitions

  • the invention disclosed herein relates to a light emitting element driving device, and a light emission control device and light emitting device using the same.
  • Patent Document 1 can be mentioned as an example of the conventional technology related to the above.
  • the light emitting element driving device disclosed herein generates a current detection signal according to the difference between a sense voltage according to the output current supplied to the light emitting element and a predetermined current setting signal.
  • the configured current sense amplifier and the error amplifier configured to generate an error signal such that the DC component of the current detection signal has a zero value are compared and set by comparing the current detection signal and the error signal.
  • the device includes a comparator configured to generate a signal, and a driver configured to perform feedback control of the output current according to the set signal.
  • a light emitting element driving device that can quickly and safely perform a lighting recovery operation when a load is open, and a light emitting control device and a light emitting device using the same. It becomes possible to do so.
  • FIG. 1 is a diagram showing the lighting return operation (continuation operation) when the LED is open.
  • FIG. 2 is a diagram illustrating an example of an operation mode required when returning to lighting.
  • FIG. 3 is a diagram showing an example of a general operation mode at the time of return to lighting.
  • FIG. 4 is a diagram showing a first embodiment of the LED lamp module.
  • FIG. 5 is a diagram showing an example of a circuit configuration in the first embodiment.
  • FIG. 6 is a diagram showing an example of signal transmission in the first embodiment.
  • FIG. 7 is a diagram showing an example of a control block in the first embodiment.
  • FIG. 8 is a diagram showing how the error signal in the first embodiment depends on the set current.
  • FIG. 9 is a diagram illustrating an example of a lighting return operation in the first embodiment.
  • FIG. 1 is a diagram showing the lighting return operation (continuation operation) when the LED is open.
  • FIG. 2 is a diagram illustrating an example of an operation mode required when returning to lighting.
  • FIG. 10 is a diagram showing the responsiveness of the output current in the first embodiment.
  • FIG. 11 is a diagram showing a second embodiment of the LED lamp module.
  • FIG. 12 is a diagram showing an example of a circuit configuration in the second embodiment.
  • FIG. 13 is a diagram showing an example of signal transmission in the second embodiment.
  • FIG. 14 is a diagram showing an example of a control block in the second embodiment.
  • FIG. 15 is a diagram showing how the error signal in the second embodiment does not depend on the set current.
  • FIG. 16 is a diagram illustrating an example of a lighting return operation in the second embodiment.
  • FIG. 17 is a diagram showing the responsiveness of output current in the second embodiment.
  • FIG. 1 is a diagram showing the lighting return operation (continuation operation) when the LED is open.
  • the LCU 10 includes an LED driver IC1 (corresponding to a light emitting element driving device), and supplies an output current ILED to the LED string 2.
  • LED driver IC1 corresponding to a light emitting element driving device
  • the LED string 2 includes a plurality of LED elements connected in series, and emits light with a brightness according to the output current ILED.
  • the matrix manager 3 includes a plurality of switch elements SW connected in parallel to each of the plurality of LED elements forming the LED string 2, and can arbitrarily control the number of series stages (lighting number) of the LED elements by turning on/off each switch element. Switch to
  • the LED lamp module Z including the matrix manager 3 can maintain the lighting state even when the LED string 2 has an open failure.
  • the open failure part of the LED string 2 is bypassed and the output current is reduced. It is possible to secure a path for the ILED to flow and return the LED string 2 to the lighting state.
  • FIG. 2 is a diagram illustrating an example of an operation mode required when returning to lighting after an LED open failure.
  • the LCU 10 especially the main LED driver IC 1
  • the LCU 10 continues to operate even in the event of an LED open failure, and immediately changes the output current ILED to the current setting value (target value) after establishing a bypass path at the open failure location. ) to quickly return the LED string 2 to the lighting state.
  • FIG. 3 is a diagram showing a general operation mode when lighting is restored from an LED open failure.
  • the LCU 10 in the general operation mode when the lighting is restored, the LCU 10 is temporarily shut down when an LED open failure is detected, and then restarted. Therefore, due to the delay in starting up the LCU 10, it takes a considerable amount of time for the LED string 2 to return to lighting.
  • the LED lamp module Z of this embodiment includes the LCU 10 and the LED string 2, as described above. Note that the previously mentioned matrix manager 3 is not shown for convenience.
  • the LCU 10 includes an LED driver IC 1 and various discrete components (in this figure, an inductor L1, a sense resistor Rs, and a capacitor Co) externally attached to the LED driver IC1.
  • various discrete components in this figure, an inductor L1, a sense resistor Rs, and a capacitor Co
  • the LED driver IC1 includes a plurality of external terminals (SW pin, SNSP pin, SNSN pin, etc.) as means for establishing electrical connection with the outside of the IC.
  • SW pin is a switch output terminal.
  • the SNSP pin is the first current sense terminal (+).
  • the SNSN pin is the second current sense terminal (-).
  • the SW pin is connected to the first end of the inductor L1.
  • a second end of the inductor L1 is connected to a first end of the sense resistor Rs.
  • the second end of the sense resistor Rs and the first end of the capacitor Co are both connected to the anode of the LED string 2.
  • the cathode of the LED string 2 and the second end of the capacitor Co are both connected to the ground end.
  • a first end (high potential end) of the sense resistor Rs is connected to the SNSP pin.
  • the second end (low potential end) of the sense resistor Rs is connected to the SNSN pin.
  • the inductor L1 and capacitor Co together with the driver 11 (particularly the upper switch 11H and lower switch 11L included in the driver 11) integrated into the LED driver IC1, form a step-down switch output stage. form.
  • the sense resistor Rs converts the inductor current IL flowing through the inductor L1 into a sense voltage Vsns.
  • the LED driver IC 1 integrates a driver 11, an on-time setting section 14, a slope signal generation section 15, an error amplifier 17, a comparator 18, a current setting section 1X, input resistors R1P and R1N, and a capacitor Cc. has been made into Of course, components other than those described above (temperature detection circuit, various protection circuits, etc.) may be integrated in the LED driver IC1.
  • the driver 11 includes an upper switch 11H and a lower switch 11L.
  • the lower switch 11L is connected between the SW pin and the PGND pin.
  • NMOSFETs N-channel type metal oxide semiconductor field effect transistors
  • the upper switch 11H and lower switch 11L connected in this way form a half-bridge type (synchronous rectification type) switch output stage that outputs a rectangular waveform switch voltage Vsw from the SW pin. That is, the upper switch 11H corresponds to an output element, and the lower switch 11L corresponds to a synchronous rectifier. Note that if a diode rectification switch output stage is employed, a rectifier diode may be used in place of the lower switch 11L.
  • the driver 11 complementarily turns on and off the upper switch 11H and the lower switch 11L according to the set signal SET and the reset signal RST, so that the output current ILED matches a predetermined current setting value (target value).
  • feedback control of the inductor current IL (and by extension, the output current ILED) is performed using a bottom detection type on-time fixed method.
  • the driver 11 turns on the upper switch 11H and turns off the lower switch 11L at the rising timing of the set signal SET, and turns off the upper switch 11H at the rising timing of the reset signal RST to turn the lower side switch 11H off. Turn on switch 11L.
  • the word “complementary” refers not only to the case where the on/off states of the upper switch 11H and the lower switch 11L are completely reversed, but also to the case where the on/off states of the upper switch 11H and the lower switch 11L are simultaneously turned off to prevent a through current. This should be understood in a broad sense, including cases where a period (so-called dead time) is provided.
  • the on-time setting unit 14 generates a pulse in the reset signal RST when a predetermined on-time Ton has elapsed since the pulse was generated in the set signal SET. In other words, the on-time setting unit 14 raises the reset signal RST to a high level when a predetermined on-time Ton has elapsed from the rising timing of the set signal SET (and the on-timing of the upper switch 11H).
  • the on-time setting section 14 may have a function of arbitrarily setting the on-time Ton.
  • the on-time setting unit 14 may also have a function of varying the on-time Ton based on the terminal voltages of the PIN pin and the SNSN pin so as to suppress fluctuations in the switching frequency Fsw.
  • the slope signal generation unit 15 generates a slope signal Vslp containing information (alternating current component) about the inductor current IL from the sense voltage Vsns applied between the non-inverting input terminal (+) and the inverting input terminal (-). . Note that the slope signal Vslp becomes higher as the inductor current IL becomes larger, and becomes lower as the inductor current IL becomes smaller.
  • the non-inverting input terminal (+) of the error amplifier 17 is connected to the SNSP pin via the input resistor R1P.
  • the inverting input terminal (-) of the error amplifier 17 is connected to the SNSN pin via an input resistor R1N.
  • a capacitor Cc is connected between the output terminal of the error amplifier 17 and the ground terminal.
  • the comparator 18 generates a set signal SET by comparing the slope signal Vslp input to the inverting input terminal (-) and the error signal Vc input to the non-inverting input terminal (+).
  • the set signal SET becomes low level when Vc ⁇ Vslp, and becomes high level when Vc>Vslp. Therefore, the lower the error signal Vc is, the later the rise timing of the set signal SET (and thus the turn-on timing of the upper switch 11H) is, and the higher the error signal Vc is, the earlier the rise timing of the set signal SET is.
  • the current setting unit 1X sets the input offset value of the error amplifier 17 (and thus the current setting value of the output current ILED) by passing a reference current through the input resistor R1P or R1N.
  • FIG. 5 is a diagram showing an example of a specific circuit configuration of the LED driver IC 1 of the first embodiment. It should be noted that the same reference numerals as in FIG. 4 are given to the components that have already appeared, and redundant explanations will be omitted, and new components and changes will be mainly explained.
  • the LED driver IC 1 of this configuration example includes a current sense amplifier 16, a current sense amplifier 16, resistors R21, R22, and a capacitor Cc. Ro is integrated.
  • the LED driver IC1 of this configuration example there is a connection between the first end (high potential end) of the sense resistor Rs and the SNSP pin, and between the second end (low potential end) of the sense resistor Rs and the SNSN pin. , are connected to current limiting resistors RpP and RpN, respectively.
  • the error signal Vc is generated by outputting a current according to the voltage and charging and discharging the capacitor Cc. Therefore, the error signal Vc rises when VISET ⁇ Vdcdim, and falls when VISET>Vdcdim.
  • a resistor ro is connected in parallel with the capacitor Cc between the output terminal of the error amplifier 17 and the ground terminal. Note that the capacitor Cc is for phase compensation. Further, the resistor ro is the output impedance of the error amplifier 17, and does not exist as an actual element.
  • the slope signal generation section 15 is a gm amplifier that operates by receiving current from the PIN pin and can detect the sense voltage Vsns appearing between both terminals without drawing current from the SNSP and SNSN pins. Note that a resistor R22 is connected between the output end of the slope signal generation section 15 and the ground end.
  • the current sense amplifier 16 operates by receiving power from the PIN pin, amplifies the sense voltage Vsns, and generates the current detection signal VISET.
  • a non-inverting input terminal (+) of the current sense amplifier 16 is connected to the SNSP pin via an input resistor R1P.
  • the inverting input terminal (-) of the current sense amplifier 16 is connected to the SNSN pin via an input resistor R1N.
  • a second end of the resistor R21 is connected to a ground terminal.
  • the current sense amplifier 16 has a first feedback current path configured to flow the first feedback current i31 between its output terminal and the non-inverting input terminal (+), and between the output terminal and the SNSN pin. and a second feedback current path configured to flow a second feedback current i31'.
  • the second feedback current i31' may be a copy (mirror current) of the first feedback current i31, or may be a copy of the first feedback current i31 given an offset.
  • the LED driver IC 1 of this configuration example has two floating amplifiers (slope signal generation unit 15 and current sense amplifier 16) that can amplify the sense voltage Vsns rail-to-rail (between the power supply potential and the ground potential). Requires. Therefore, it must be noted that the circuit area increases. Note that “floating” in this specification means floating from the ground potential (separated from the ground potential).
  • the symbol Gcs indicates the gain of the slope signal generation section 15.
  • the symbol Gsns indicates the gain of the current sense amplifier 16.
  • the symbol ⁇ Vsns indicates the sense voltage Vsns.
  • the symbol X indicates a current setting value (target value) of the output current ILED.
  • the symbol ⁇ Vc indicates the error signal Vc.
  • ⁇ D indicates the off-duty of the lower switch 11L (control of the bottom value of the inductor current IL ⁇ control of the off period).
  • the symbol Cc indicates the capacitance value of the capacitor Cc.
  • FIG. 7 is a diagram showing an example of a control block in the LED driver IC 1 of the first embodiment.
  • the control block A in this figure is a functionally rewritten version of the error amplifier 17 in FIG. 4, and includes a subtracter A1 and an amplifier A2.
  • FIG. 8 is a diagram showing how the error signal Vc in the LED driver IC1 of the first embodiment depends on the setting current ISET.
  • the bottom value of the inductor current IL (more precisely, the inductor current Comparison control is performed between the bottom value of the slope signal Vslp (corresponding to current information of IL) and the error signal Vc.
  • the error signal Vc rises following the set current ISET, and the bottom value of the inductor current IL also rises.
  • the average inductor current IL_ave converges to the set current ISET after being pulled up.
  • FIG. 9 is a diagram showing an example of a lighting return operation in the LED driver IC 1 of the first embodiment. Note that the behavior of the inductor current IL is shown in the upper part of the figure. Furthermore, the behavior of the slope signal Vslp and the error signal Vc is shown in the lower part of the figure.
  • the inductor current IL stops flowing and the sense voltage Vsns is not generated (output feedback control does not work). If the LED driver IC1 continues to operate in this state, the slope signal Vslp decreases to a low level (GND level), and the error signal Vc increases to an upper limit value VcH (outside the control range in steady state).
  • a possible measure to prevent the occurrence of such overcurrent is to temporarily shut down the LED driver IC1 when an LED open failure is detected, and then restart it (see Figure 3 above). .
  • FIG. 10 is a diagram showing the responsiveness of the output current ILED in the LED driver IC1 of the first embodiment, and depicts the error signal Vc, the inductor current IL, and the setting current ISET in order from the top.
  • the error signal Vc has dependence on the set current ISET.
  • the set current ISET is raised, the error signal Vc first rises, and the inductor current IL follows this and converges to the target value.
  • the time T1 required for the inductor current IL to converge to the target value is approximately several hundred ⁇ s.
  • the responsiveness of the inductor current IL (and thus the output current ILED) to the set current ISET is poor.
  • FIG. 11 is a diagram showing a second embodiment of the LED lamp module Z.
  • the LED lamp module Z of this embodiment is based on the previously described first embodiment (FIGS. 4 and 5), but the internal configuration (especially the output feedback system) of the LED driver IC 1 has been modified. Therefore, the constituent elements that have already appeared are given the same reference numerals as those in FIG. 4, and redundant explanations will be omitted, and the explanation will focus on the new constituent elements and changes.
  • the current sense amplifier 16 has a sense voltage Vsns corresponding to the inductor current IL (and by extension, the output current ILED) and a predetermined current setting signal (for example, an offset voltage according to the setting current ISET).
  • the slope signal generation section 15 mentioned above is removed, and the output terminal of the current sense amplifier 16 is connected to the inverting input terminal (-) of the error amplifier 17 and the comparator 18.
  • a current detection signal Vcso is output.
  • the error amplifier 17 outputs an error signal Vc according to the difference between the current detection signal Vcso input to the inverting input terminal (-) and the reference voltage Vref input to the non-inverting input terminal (+). In other words, the error amplifier 17 generates the error signal Vc so that the DC component of the current detection signal Vcso has a zero value.
  • the comparator 18 generates a set signal SET by comparing the current detection signal Vcso input to the inverting input terminal (-) and the error signal Vc input to the non-inverting input terminal (+).
  • the set signal SET becomes low level when Vc ⁇ Vcso, and becomes high level when Vc>Vsco. Therefore, the lower the error signal Vc is, the later the rise timing of the set signal SET (and thus the turn-on timing of the upper switch 11H) is, and the higher the error signal Vc is, the earlier the rise timing of the set signal SET is.
  • the driver 11 turns on the upper switch 11H and turns off the lower switch 11L at the rising timing of the set signal SET, and also turns off the upper switch 11H and turns on the lower switch 11L at the rising timing of the reset signal RST.
  • the driver 11 turns on the upper switch 11H and turns off the lower switch 11L when the current detection signal Vcso drops to the error signal Vc, and also when a predetermined on-time Ton has elapsed from the on-timing of the upper switch 11H. At this point, the upper switch 11H is turned off and the lower switch 11L is turned on.
  • the driver 11 turns on and off the upper switch 11H and the lower switch 11L in a complementary manner according to the set signal SET and the reset signal RST, so that the output current ILED reaches a predetermined current setting value (target value).
  • Feedback control of the inductor current IL (and by extension, the output current ILED) is performed using a bottom detection type fixed on-time method so as to match the above.
  • the LED driver IC 1 of this embodiment further includes a clamper 1Y that limits the error signal Vc to a predetermined upper limit value VcH or less.
  • the clamper 1Y is an operational amplifier to which the upper limit value VcH of the error signal Vc is applied to the non-inverting input terminal (+), and whose inverting input terminal (-) and output terminal are connected to the application terminal of the error signal Vc. Good too.
  • FIG. 12 is a diagram showing an example of a specific circuit configuration of the LED driver IC 1 in the second embodiment. It should be noted that the same reference numerals as in FIG. 11 are given to the components that have already appeared, and redundant explanations will be omitted, and new components and changes will be mainly explained.
  • the LED driver IC 1 of this configuration example includes a bias amplifier 1A, and a VI converter. 1B, transistors P1a and P1b (for example, PMOSFET [P-channel type MOSFET]), and resistors R31a, R31b, R32a, R32b, R33, R34a, R34b, and Ro are integrated.
  • transistors P1a and P1b for example, PMOSFET [P-channel type MOSFET]
  • resistors R31a, R31b, R32a, R32b, R33, R34a, R34b, and Ro are integrated.
  • the LED driver IC1 of this embodiment includes a second reference current path configured to flow a second reference current i41' between the SNSN pin and the second output terminal of the VI converter 1B.
  • the first reference current i41 and the second reference current i41' may have the same value, or an arbitrary offset may be provided between them.
  • the current limiting resistor RpP and the current limiting resistor RpP are connected to the SNSP pin and the SNSN pin respectively. Even if RpN is externally connected, the gain of the VI converter 1B (and by extension the reference voltage of the current sense amplifier 16) is uniquely determined according to the ratio of the input resistor R1P and the resistor R33, so the LED driver IC1 It becomes possible to eliminate the decrease in current detection accuracy (particularly temperature drift).
  • the second differential output terminal of the current sense amplifier 16 is connected to the first terminal of the resistor R31b, and is also connected to the non-inverting input terminal (+) of the error amplifier 17.
  • the second ends of the resistors R31a and R31b are both connected to a ground terminal.
  • resistors R32a and R32b are connected in series between the non-inverting input terminal (+) and the inverting input terminal (-) of the current sense amplifier 16, and the current sense amplifier 16 is driven from the connection node between them. Voltage is supplied.
  • the error amplifier 17 outputs a current according to the current detection signal ⁇ Vcso that is differentially input between the non-inverting input terminal (+) and the inverting input terminal (-), and charges and discharges the capacitor Cc to eliminate the error. Generates signal Vc.
  • a resistor ro is connected in parallel with the capacitor Cc between the output terminal of the error amplifier 17 and the ground terminal. Note that the capacitor Cc is for phase compensation. Further, the resistor ro is the output impedance of the error amplifier 17, and does not exist as an actual element.
  • the gate of the transistor P1a is connected to the first differential output terminal of the current sense amplifier 16.
  • the drain of transistor P1a is connected to a ground terminal.
  • the source of transistor P1a is connected to the first end of resistor R34a.
  • the second end of the resistor R34a is connected to the inverting input end (-) of the comparator 18.
  • the transistor P1a connected in this manner functions as a first voltage follower (first source follower) connected between the first differential output terminal of the current sense amplifier 16 and the inverting input terminal (-) of the comparator 18. do.
  • the gate of the transistor P1b is connected to the second differential output terminal of the current sense amplifier 16.
  • the drain of transistor P1b is connected to the ground terminal.
  • the source of transistor P1b is connected to the first end of resistor R34b.
  • the second end of the resistor R34b is connected to the non-inverting input end (+) of the comparator 18.
  • the transistor P1b connected in this manner functions as a second voltage follower (second source follower) connected between the second differential output terminal of the current sense amplifier 16 and the non-inverting input terminal (+) of the comparator 18. Function.
  • the bias amplifier 1A applies a differential signal to each of the resistors R34a and R34b according to the difference between the error signal Vc input to the non-inverting input terminal (+) and the bias voltage Vbias input to the inverting input terminal (-). By outputting current, the respective operating points of the first voltage follower and the second voltage follower are determined.
  • the logic level of the set signal SET is switched when (VcsoP-Vc)-(VcsoN+Vc)>0, that is, when ⁇ Vcso-2Vc>0.
  • the bottom value of the inductor current IL is detected at the point where the current information ⁇ Vcso reaches the control voltage Vc.
  • the differential input difference of the current sense amplifier 16 will be 0 (DC error is 0), so the current difference between the SNSP pin and the SNSN pin will be Does not occur.
  • the slope signal generation section 15 can be integrated into the current sense amplifier 16 to reduce the circuit scale.
  • the symbol Gsns indicates the gain of the current sense amplifier 16.
  • the symbol ⁇ Vsns indicates the sense voltage Vsns.
  • the symbol X indicates a current setting value (target value) of the output current ILED.
  • the symbol ⁇ Vc indicates the error signal Vc.
  • ⁇ D indicates the off-duty of the lower switch 11L (control of the bottom value of the inductor current IL ⁇ control of the off period).
  • the symbol Cc indicates the capacitance value of the capacitor Cc.
  • FIG. 14 is a diagram showing an example of a control block in the LED driver IC 1 of the second embodiment.
  • Control block B in this figure is a functionally rewritten version of the current sense amplifier 16 and error amplifier 17 in FIG. 12, and includes a subtracter B1 and an amplifier B2.
  • FIG. 15 is a diagram showing how the error signal Vc in the LED driver IC1 of the second embodiment does not depend on the set current ISET.
  • FIG. 16 is a diagram showing an example of the lighting return operation in the LED driver IC 1 of the second embodiment. Note that the behavior of the inductor current IL is shown in the upper part of the figure. Furthermore, the behavior of the current detection signal Vcso and the error signal Vc is shown in the lower part of the figure.
  • the inductor current IL stops flowing, resulting in a state in which the sense voltage Vsns is not generated (output feedback control does not work). If the LED driver IC1 continues to operate in this state, the current detection signal Vcso drops to a low level (GND level), and the error signal Vc rises to the upper limit value VcH.
  • the error signal Vc is stuck at the upper limit value VcH.
  • FIG. 17 is a diagram showing the responsiveness of the output current ILED in the LED driver IC1 of the second embodiment, and depicts the error signal Vc, the inductor current IL, and the setting current ISET in order from the top.
  • the error signal Vc has no dependence on the set current ISET. Therefore, even if the set current ISET is raised, the error signal Vc does not change, and the inductor current IL converges to the target value without delay. Note that the time T2 required for the inductor current IL to converge to the target value is only about several ⁇ s.
  • the LED driver IC 1 of the second embodiment not only can quickly and safely perform the lighting recovery operation in the event of an LED open failure, but also can reduce the inductor current IL (and the output current ILED) with respect to the set current ISET. ) can also significantly improve responsiveness.
  • the light emitting element driving device disclosed herein generates a current detection signal according to the difference between a sense voltage according to the output current supplied to the light emitting element and a predetermined current setting signal.
  • the configured current sense amplifier and the error amplifier configured to generate an error signal such that the DC component of the current detection signal has a zero value are compared and set by comparing the current detection signal and the error signal.
  • a configuration includes a comparator configured to generate a signal, and a driver configured to perform feedback control of the output current according to the set signal.
  • the light emitting element driving device may further include a clamper configured to limit the error signal to a predetermined upper limit value or less (second configuration).
  • a first differential output terminal and a second differential output terminal of the current sense amplifier are connected to an inverting input terminal and a non-inverting input terminal of the error amplifier, respectively.
  • a connected configuration (third configuration) may also be used.
  • the light emitting device driving device includes a first voltage follower configured to be connected between the first differential output terminal of the current sense amplifier and an inverting input terminal of the comparator; further comprising a second voltage follower configured to be connected between the second differential output terminal of the current sense amplifier and a non-inverting input terminal of the comparator, the error signal being connected between the second differential output terminal and the non-inverting input terminal of the comparator;
  • a configuration (fourth configuration) may be adopted in which the voltage is subtracted from the output signal of the follower and added to the output signal of the second voltage follower.
  • the driver may be of a half-bridge type including an upper switch and a lower switch (fifth configuration).
  • the driver turns on the upper switch and turns off the lower switch when the current detection signal decreases to the error signal, and also turns on the upper switch.
  • a configuration (sixth configuration) may be adopted in which the upper switch is turned off and the lower switch is turned on when a predetermined on-time period has elapsed from the on-timing.
  • the light emitting element driving device further includes an on-time setting section configured to generate a pulse on the reset signal when the on-time has elapsed since the pulse was generated on the set signal,
  • the driver may have a configuration (seventh configuration) that performs feedback control of the output current using a bottom detection type on-time fixed method in response to the set signal and the reset signal.
  • the light emission control device disclosed in this specification is configured to form a switch output stage together with the light emitting element driving device having any of the first to seventh configurations and a switch element included in the driver.
  • the eighth configuration includes an inductor and a capacitor configured as follows, and a sense resistor configured to convert an inductor current flowing through the inductor into the sense voltage.
  • the light-emitting device disclosed in this specification includes a light-emission control device according to the eighth configuration, and a light-emitting element configured to receive the output current from the light-emission control device.
  • a configuration (ninth configuration) is provided.
  • the light emitting device may further include a switch control device configured to arbitrarily switch the number of series stages of the light emitting elements (tenth configuration).
  • LED driver IC (light emitting element driving device) 10 LCU (light emission control unit) 2 LED string (light emitting element) 3 Matrix manager (switch control device) 11 Driver 11H Upper switch (NMOSFET) 11L lower switch (NMOSFET) 14 On-time setting section 15 Slope signal generation section 16 Current sense amplifier 17 Error amplifier 18 Comparator 1X Current setting section 1Y Clamper 1A Bias amplifier 1B VI converter A, B Control block A1, B1 Subtractor A2, B2 Amplifier Cc , Co Capacitor L1 Inductor P1a, P1b Transistor (PMOSFET) R1P, R1N Input resistance R21, R22, R31a, R31b, R32a, R32b, R33, R34a, R34b, ro Resistance RpP, RpN Current limiting resistance Rs Sense resistance SW Switch element Z LED lamp module (light emitting device)

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Led Devices (AREA)
PCT/JP2023/005649 2022-03-31 2023-02-17 発光素子駆動装置、発光制御装置、発光装置 Ceased WO2023188964A1 (ja)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE112023001176.1T DE112023001176T5 (de) 2022-03-31 2023-02-17 Treibervorrichtung für ein lichtemittierendes element, lichtemissionssteuerungsvorrichtung, und lichtemissionsvorrichtung
JP2024511415A JPWO2023188964A1 (https=) 2022-03-31 2023-02-17
CN202380031521.0A CN118975406A (zh) 2022-03-31 2023-02-17 发光元件驱动装置、发光控制装置、发光装置
US18/895,569 US20250024568A1 (en) 2022-03-31 2024-09-25 Light-emitting element drive device, light emission control device, and light emission device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022060370 2022-03-31
JP2022-060370 2022-03-31

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/895,569 Continuation US20250024568A1 (en) 2022-03-31 2024-09-25 Light-emitting element drive device, light emission control device, and light emission device

Publications (1)

Publication Number Publication Date
WO2023188964A1 true WO2023188964A1 (ja) 2023-10-05

Family

ID=88200283

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/005649 Ceased WO2023188964A1 (ja) 2022-03-31 2023-02-17 発光素子駆動装置、発光制御装置、発光装置

Country Status (5)

Country Link
US (1) US20250024568A1 (https=)
JP (1) JPWO2023188964A1 (https=)
CN (1) CN118975406A (https=)
DE (1) DE112023001176T5 (https=)
WO (1) WO2023188964A1 (https=)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4642164A1 (en) * 2024-04-24 2025-10-29 Tridonic GmbH & Co. KG Led driver for supplying an led load with a dc voltage

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118975112A (zh) * 2022-03-31 2024-11-15 罗姆股份有限公司 半导体装置、模块
CN119789266A (zh) * 2025-03-11 2025-04-08 华源智信半导体(深圳)有限公司 Led驱动电路及电子设备

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008288207A (ja) * 2007-05-18 2008-11-27 Samsung Electro-Mechanics Co Ltd Ｌｅｄアレイ駆動装置
JP2021044283A (ja) * 2019-09-06 2021-03-18 ローム株式会社 発光素子駆動装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008288207A (ja) * 2007-05-18 2008-11-27 Samsung Electro-Mechanics Co Ltd Ｌｅｄアレイ駆動装置
JP2021044283A (ja) * 2019-09-06 2021-03-18 ローム株式会社 発光素子駆動装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4642164A1 (en) * 2024-04-24 2025-10-29 Tridonic GmbH & Co. KG Led driver for supplying an led load with a dc voltage

Also Published As

Publication number Publication date
CN118975406A (zh) 2024-11-15
US20250024568A1 (en) 2025-01-16
DE112023001176T5 (de) 2024-12-19
JPWO2023188964A1 (https=) 2023-10-05

Similar Documents

Publication Publication Date Title
WO2023188964A1 (ja) 発光素子駆動装置、発光制御装置、発光装置
CN100405720C (zh) Dc/dc转换器
JP4510022B2 (ja) 電源装置およびそれを用いた電子機器
US7679351B2 (en) Power supply apparatus
US11265981B2 (en) Light emitting element driving device
JP2012059050A (ja) レギュレータ及びｄｃ／ｄｃコンバータ
KR20070044755A (ko) Ｄｃ-ｄｃ 컨버터, ｄｃ-ｄｃ 컨버터의 제어 회로 및ｄｃ-ｄｃ 컨버터의 제어 방법
KR20100086995A (ko) 전원 장치
JP7520668B2 (ja) 電流検出回路
US20250016896A1 (en) Semiconductor device and module
US9531259B2 (en) Power supply circuit
US7336057B2 (en) DC/DC converter
US12355354B2 (en) Switching power supply circuit and switching power supply device
WO2007074866A1 (ja) 発光素子駆動回路
CN112351551A (zh) 调光电路
EP1718132B1 (en) Load failure protection circuit and discharge lamp driving apparatus
JP2024053910A (ja) 降圧ｄｃ／ｄｃコンバータのコントローラ回路、車載電源システム
US12580470B2 (en) Detector circuit having current conversion mechanism for power converter
JP5666694B2 (ja) 負荷電流検出回路
WO2023002852A1 (ja) 半導体装置、スイッチング電源、発光装置
JP7626673B2 (ja) 昇圧ｄｃ／ｄｃコンバータの制御回路、電源回路、電子機器
US20220286126A1 (en) Output device
JP2023035422A (ja) 発光素子駆動用半導体集積回路、発光素子駆動装置、発光装置、車両
JP2024083794A (ja) 電源制御装置
JP2000066747A (ja) 定電圧回路及びその定電圧出力方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23778994

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2024511415

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 202380031521.0

Country of ref document: CN

WWE Wipo information: entry into national phase

Ref document number: 112023001176

Country of ref document: DE

122 Ep: pct application non-entry in european phase

Ref document number: 23778994

Country of ref document: EP

Kind code of ref document: A1