TWM339153U - DC output circuit with current detecting device - Google Patents

Description

M339153 严)·2; VIII. New Description: L——— [New Technology Field] This creation is about a current detecting device, especially a current detecting device that can be applied to a DC output circuit. [Prior Art] The feedback control system controls the output voltage or the output current to stabilize at a predetermined value by detecting the output voltage or current state. Voltage ® feedback control is generally performed by a voltage divider parallel load, which returns the voltage across the load to the controller, so that the controller can control the power output to the load to achieve a stable output voltage. The current feedback control generally returns the current state flowing through the load to the controller through a resistor series load, so that the controller controls the power output to the load to achieve the purpose of stabilizing the output current. The above detection of output voltage or output current will cause partial φ energy loss. In particular, current detection, because of the instability of the feedback control in order to avoid the interference of noise, the voltage across the current detection resistor cannot be reduced indefinitely, generally about 0.5-0.8 volts. However, in the face of low-voltage-driven LEDs, the efficiency caused by current detection is reduced, generally around 3%, and even higher than 5%. Such high power consumption is obviously not in line with the mainstream value of environmental awareness under the current high energy costs. Referring to the first figure, a light-emitting diode driving circuit which is common in the prior art. As shown in the first figure, the LED driving circuit comprises a light emitting diode module 10, a current balancing circuit 20, a current detecting resistor 30, and a 9ΐΜ33 brain ^ r ^ ^-^1·1 year Nightmare f

One worry (PWM) control descent 40 and one liter repeated conversion circuit 5 〇. The light-emitting diode module 10 includes a plurality of parallel-connected light-emitting diode groups. The regulation of the current balancing circuit 20 causes each of the light-emitting diode groups to flow through approximately the same current to emit approximately the same brightness. The current balancing circuit Μ includes a plurality of NMOS transistors. The source and the gate of each NM 〇s transistor are connected to each other, wherein: the ring of the Gang S transistor (the leftmost side in the figure) and the gate are connected to form - Current mirror. The current detecting resistor 3 Q detects the current value flowing through the light emitting diode module 1G, and converts it into a voltage signal Vr output to the PWM t system 40. The PWM controller 40_ is connected to the 'turn voltage VDD and ground, sub-output-control signal to regulate the output power of the boost converter circuit %. The pulse width of the 5-th control signal is adjusted according to the voltage signal %. The boost converter circuit 5 converts the power of the DC input voltage Vin into a DC output voltage according to the control signal of the P WM controller to drive the LED module 10. As explained above, the current detecting circuit a 30 causes a voltage drop Vr, and the MOS transistor in the current balancing circuit 20 also causes a turn-on voltage drop. Obviously, such a circuit architecture τ ' power conversion efficiency is not high. Further, in addition to the boost converter circuit in the first figure, the light-emitting diode drive circuit also has a negative output voltage conversion circuit or the like to match different applications. In order to be able to handle a variety of different application circuits, the _ salt controller 4 (): D j and one of the ground must be connected to the output voltage, resulting in the control of the 咼 withstand voltage capability, increase PW1V [controller cost. [New content] M339153 ^ Drink the voltage drop caused by the current-sense resistor to improve the power conversion efficiency. Another k is private, #>~咕+ 'The pen mirror directly outputs the current signal, so the + bit conversion, the current detection signal can be easily converted into the level range that the PWM controller can handle without lifting The pwM controller's withstand voltage capability matches the current sense signal.

In order to achieve the above objectives, the present invention provides a current detecting device comprising a balanced current unit and a detecting unit. The balanced current unit includes a reference terminal for connecting one carrier and flowing through the reference current. The upper cutting unit is connected to the balancing current unit and has a detecting end, and the detecting unit m measures the money, wherein the detecting current is a predetermined ratio mirroring the reference current. This creation also provides a DC circuit that includes a conversion circuit, -m and ~ controller. The above-mentioned conversion is connected to the input voltage and is converted into a constant voltage to the load according to the control. The current_device includes an electric (10)4 current mirror according to a load flowing through the load, and the current mirror includes a common terminal, and the current mirror includes a common terminal. And at least one mirror end, wherein one of the at least one mirror end is a detecting device, and the controller is lightly connected to the controller and the image is copied by the proportional image to generate the ♦ and X stream detection signals. The reference ~ and the other end of the at least one mirror end engage the 兮β load sub-current through the negative torrent flow, and the common end is coupled to the reference level. The upper block is pressed and grounded and driven by the drive decompression drive 4 - drive power, and the read controller is coupled to the switch ♦ circuit device and the current mirror, and generates the current detector, package, and test Control

Adjusting the magnitude of the load current [Embodiment] The spirit of the present invention is to use a current mirror to replicate the output voltage of the output. Since the private current has no limit, it can be converted into a voltage signal by providing an appropriate reference potential. It is processed by the PWM controller, so it can avoid the problem that the current (four) signal level cannot be processed by the PWM control lion, or the PWM control & in turn, cooperate with the Xianhao signal level. Furthermore, for the illuminating-polar body driving circuit, in order to achieve a similar current of each string of light-emitting diode groups, a similarly close current is emitted, and a current mirror is required, so that the current mirror is directly used as the current Detector. The measuring device not only does not require an additional cost burden, but also eliminates the cost of the current detecting resistor and the resulting decrease in power conversion efficiency. First, the structure of the current detecting device of the present invention will be first introduced. Please refer to the first figure, which is a circuit diagram of a current detecting device according to an embodiment of the present invention. The current detecting device includes a balancing current unit 122 and a detecting unit 124. The balancing current unit 122 is coupled to a load and includes a reference MOS transistor. The reference MOS transistor is substantially a reference terminal 122a' and the drain is connected to the gate and the source is coupled to ground. The detecting unit 124 is connected to the balancing current unit 122 and has a detecting end 122a. The detecting unit 124 includes a detecting MOS transistor, and the gate and the immersion of the MOS transistor are respectively connected to the pole and the drain of the reference MOS transistor. Thus, the 'side reference MOS transistor and the MOS transistor form a current mirror. When the reference terminal 122a flows through the current II, the detecting terminal 124a generates the M339153 ^ Detecting current is, wherein the measurement The current Is is a predetermined ratio of the clothing 忒 = test current. In this embodiment, the aspect ratio (W/L) of the reference MOS transistor and the MOS transistor is η: ι, thus I1/Is^n. 2 As described above, the current state of the load can be transmitted through the current detection of the present invention: the reaction is reflected to the detection end, so that the control circuit can adjust the current of the load according to the size of the detected end of the detection terminal to reach back. Control function. When the load is a light-emitting diode module, since the light-emitting diode module often has a plurality of strings of light-emitting diodes, the current detecting device of the present invention can have more and less one output end to match The LED module is driven as follows. As shown in the second figure, the balancing current unit 122 further includes two output gold transistors, and the output of the metal oxide transistors is an output terminal > b And 122C. The gates and sources of the output MOS transistors are respectively connected to the gates and sources of the reference MOS transistors to form an electron mirror. Thus, the current n flowing through the reference terminal H2a is approximately equal to the currents I2, I3 flowing through the wheel terminal 122 = l*22c (in the present embodiment, the width of the reference gold-oxide half-crystal and the output metal-half transistor) The length is the same). Thus, the groups of light-emitting diodes respectively coupled to the reference terminal 122a and the output terminals 122b, 122c will flow approximately equal currents to emit approximately equal brightness. Next, please refer to the third figure, which is a DC-to-DC converter according to an embodiment of the present invention. In this embodiment, a description will be given by taking an example of driving a light-emitting diode module. The DC-to-DC converter described above includes a current detecting device 12A, a controller 140, and a conversion circuit 150. The conversion circuit 15 is lightly connected to an input voltage Vin, and converts the input voltage Vin into a DC output voltage v〇ut to a light-emitting one according to a control signal of the controller 140.

Supplement ♦ « Potential button 110. The current mirror comprises a plurality of MOS transistors, wherein the gate of the MOS transistor is connected to the drain to generate a reference current U, so that other MOS transistors generate a proportional current I2 accordingly. I3, Is. In the present embodiment, the conversion circuit 15 is a boost converter (b〇 & t converter), and includes an inductor L, a capacitor c, a diode 〇, and a ~: rate switch SW. The inductor L has one end coupled to the input voltage vin and the other end connected to the power switch SW and the diode D. The positive terminal of the diode D is connected to the inductor B, and the negative terminal is connected to the capacitor C for use as a rectification. Capacitor c is connected to the body D at one end and grounded at the other end to regulate and output an output DC voltage Vout. The power switch SW is connected between the inductor L and the ground, and the control signal of the controller 140 is switched on/off. The controller H0 is coupled between a driving voltage VDD and a ground, and determines a pulse width of the control signal according to a current detecting signal of the current detecting device 120, and the ratio of the on/off of the power switch SW is controlled by the controller. In order to control the power output to the LED module 11 to achieve stable output current. A resistor R is connected between the detecting end of the current detecting device 12 and the driving voltage VDD, and the detecting current Is flows through the resistor R to generate a current detecting signal. The controller 140 includes an undervoltage lockout (UVL0) 141, a snubber 142, a pulse width modulation comparator 143, an error amplifier 144, and a control unit 149. The undervoltage lockout 141 is configured to determine whether the driving voltage VDD has reached a predetermined voltage level, and if so, a signal is sent to notify the control unit 149 to start operating. The oscillator 142 generates a ramp signal to the pulse width modulation comparator 143. The error amplifier 144 receives the current M339153 detection signal and a reference voltage (VDD_Vref), and generates a "tea break" signal. To pulse width modulation comparator M3. Since the common potential of the current measuring device 12A and the controller 140 is VDD, the reference voltage (vdd_vre^) is generated according to the driving voltage VDD, that is, the voltage difference of the reference voltage (Vdd_v(10) gas driving voltage VDD is a fixed value Vref. The pulse width modulation comparator 143 compares the ramp signal and the error amplification signal to output a pulse width modulation signal to the control unit 149. The control unit receives the signal of the undervoltage lockout (4), and the pulse width modulation The pulse width modulation signal of the comparator 143 and the dimming signal DIM are used to output the control signal of the control unit _ switch SW according to the output control 143. Compared with the LED driving circuit of the Knife Light and Light Technology, When the lightning flow side device of the present invention is applied to the LED driving circuit, the voltage drop caused by the current can be reduced, and the power conversion efficiency of the conversion circuit can be improved. The created current detecting device 120 can also be combined with the controller, 14 —同—(D/O or package (Paekage), the layout of the drive circuit can be more::: The current of this creation can be applied to the DC turn-off conversion state 'including, but not limited to, JI, VI conversion Crying, etc. to τ = Converter, AC to DC to U叮, and then provide several real means to change the application. The current of the forest is based on the fourth picture, which is a DC converter according to another embodiment of the present invention. In the third figure, the current detecting device (10) and the control unit of the four graphs are used to control the potential, so that the controller (10) ====the same potential is turned into the ground. ρΛ1, Λ/Γ The design of the reference voltage generator is the same as that of the conventional fish controller, that is, the creation can also directly use the conventional PWM' controller to achieve the same function. 11Q 'Current detection I set 120a and the LED module Group = V Continuation of the common ground of the coffee. Phase 2: Legend 'current detection device 12 〇 a = current mirror with nHf6 (four) ground. Second, 丨〇 126b, one brother two watcher di 19A and a second mirror The end 126c, the first _ stationing reference 126a is connected to the detecting end of the current detecting, the second mirroring end 126c is coupled to the arbitrarily crying _ = by = electric "equal ratio produces a mirror two: medium, structure T"Caf VDD. In the first embodiment, the configuration is performed by taking a bipolar junction type transistor as an example: a brother-current mirror 126 is a two-pole junction type electric bipolar junction (four) • the base and the collector of the bipolar junction type transistor of the emitter and the base of each other are connected to the tough t-stream detecting device u〇a Measure the end of the test. Two pairs of poles are connected = 1: The shot is extremely second common end i26b. Corresponding to the second mirror end 26^ pole-joined transistor collector key - resistor R, flow detection ima common tr Controller, 140 and electricity

Vref ^ R is set to 〇V (ground), so the reference voltage

Vref is based on the ground potential and the voltage difference is a fixed value.纟 参考 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Change to double pole to connect 12

M339153 / r" * R S gold and y-type transistors are implemented. The current detecting device 120 includes a flat H-day unit 122 and a detecting unit 124. The balanced current unit 122 includes: a bipolar junction type transistor 122& and at least one output bipolar junction type of electric crystals 122b, 122c. One of the reference bipolar junction type transistors 122a is based on the base of the at least output bipolar junction type transistors 122b, 122e = one of the emitters of the reference bipolar junction type transistor 122a and the at least one The emitters of the pole junction type transistors 122b, 122c are connected. The reference double: the collector of the type transistor 122a serves as the reference terminal and is connected to the base of the ohmic reference bipolar junction type transistor 122a, and the at least one output 电^ junction type transistor 122b, 122c The collector is used as the above to the end. The detecting unit 124 includes a bipolar junction type transistor 12 such as a mirror. The base of the bipolar junction type transistor 124a is connected to the base of the reference bipolar transistor 122a, and the emitter of the bipolar junction type transistor 122a is connected to the emitter of the reference bipolar junction type 122a. The end of the current mirror. The mirror end of the current mirror generates a proportional mirror current Is' according to the detected current k flowing through the detecting end, and is generated after the resistor R. The current debt test is next to the sixth figure, which is the third figure. Another variation of the embodiment is shown. The difference from the embodiment shown in FIG. 3 is that the current extraction device 120 of the sixth figure is coupled between the DC output voltage v〇m and the LED module 110. In order to have a common level between the current debt measuring device 12 and the controller (10), the current_device (10) is grounded through the resistor (or can be coupled to the driving voltage VDD). Wherein, the resistance r, if the detecting end of the current detecting device 120 only passes through the resistance ruler, the voltage difference between the source and the drain of the 13-town 153 gold-oxygen semiconductor is too large, which not only affects the current detection. In addition to the accuracy, the withstand voltage requirement of the current detecting device 120 is also increased, and the above problem can be avoided by increasing the resistance R'. Referring to the seventh figure, there is shown a circuit diagram of a DC-to-DC converter according to an embodiment of the present invention. The conversion ratio (_Vout/Vin) of the conversion circuit in this embodiment is -D/(l-D), that is, the DC output voltage -Vout is a negative voltage. Similarly, in order to have a common potential between the current detecting device 120 and the controller 140, the current detecting device 120 is connected to the driving voltage VDD. The difference from the above-mentioned embodiment is that the detection unit of the current detecting device 120 further includes a level adjusting unit 128 for making the reference end in the current detecting device 120. It is exactly the same as the potential of the three terminals of the transistor at the detecting end, so that the current Π is completely consistent with Is. The level adjusting unit 128 can be a voltage follower coupled between the drain of the MOS transistor corresponding to the detecting end and the drain of the MOS transistor of the reference end, so that the Detector The voltage level of the drain of the gold-oxide semi-transistor of the measuring unit is approximately equal to the voltage level of the drain of the reference gold-oxide semiconductor. In addition, a transistor 129 is coupled between the detecting end and the resistor R. The gate of the transistor is connected to the drain, so that the voltage across the transistor 129 can be adjusted according to the DC output voltage. Referring to the eighth diagram, there is shown a circuit diagram of a DC-to-DC converter according to another embodiment of the present invention. In this embodiment, the biggest difference from the foregoing embodiments is that the detecting unit 124 includes two sets of current mirrors. The common terminal of the first set of current mirrors is connected to a reference level -Vout', and the reference level -Vout' can be equal to the DC output voltage -Vout or its partial voltage. The first 14 M339153 97. Year ‘°Day = the reference end of the current mirror is generated in proportion to the current_device i2, (iv)—mirror_current Is,. The common terminal is connected to the driving voltage v DD , and the end of the 甩 muscle mirror, and the image of the current mirror is generated in proportion to the mirror end. As described above, the current is 1S”. The signal is converted into a controller. Handling the two positions can be easy to use the current detection controller (four) Μ ability to cooperate with the dry circumference, without the need to increase the PWM resistance to reduce the _ drop, money. Can also save the current Detection. W power conversion efficiency, simplify the circuit Cloth and Figure I: The application of the patent application is only described in the detailed description of the preferred embodiment of the present invention. 'All the scope of this creation should be based on the following guide, and God and its similar changes. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ BRIEF DESCRIPTION OF THE DRAWINGS The figure is a circuit diagram of a light-emitting diode driving circuit in the prior art. The circuit is intended to correct the circuit of the current detecting device according to an embodiment of the present invention. 丨, y converter diagram Implemented according to this creation DC to DC to 15 γ years j.:i : n ^ I a component symbol description] LED module 10 current balancing circuit 20 current detection resistor 30 pulse width modulation controller 40 boost converter circuit 50 Diode module 110 current detecting device 120, 120a balancing current unit 122 reference terminal 122a output terminal 122b, 122c detecting unit 124 detecting terminal 124a second current mirror 126 second reference terminal 126a second common terminal 126b second Mirror end 126c level adjustment unit 128 transistor 129 controller 140 undervoltage locker 141 oscillator 142 pulse width modulation comparator 143 error amplifier 144 16 M339153 control unit conversion circuit capacitor dimmer dimming signal current inductor power switch resistance Drive voltage input voltage DC output voltage reference level voltage drop 149

150 C D

DIM

II~13, Is~Is" L

SW

R

VDD

Vin

Vout Λ -Vout -Vout,

Vr

17

Claims (1)

γ^4239153 篇., 丨九::: Please ask for a patent range: 1. A current sensing device comprising: a balanced current unit comprising a reference end for coupling to a load, the McCaw end flowing through A test current, and a detecting unit connected to the current unit and having a detecting end, the detecting unit generates a detecting current, wherein the detecting current copies the reference current in a predetermined ratio. 2. The current detecting device of claim 1, wherein the balancing current unit further comprises at least one output, each of the at least one output being coupled to the load and flowing through the reference current. A current. 3. The current detecting device of claim 2, wherein the balancing current unit comprises a reference MOS transistor and at least one output MOS transistor, wherein the reference MOS transistor a gate is connected to the gate of the at least one output MOS transistor, and a source of the reference MOS transistor is connected to a source of the at least one output MOS transistor, the reference MOS transistor One of the reference terminals is connected to the gate of the reference MOS transistor, and the at least one output MOS transistor is substantially at least one output end. 4. The current detecting device of claim 3, wherein the detecting unit comprises a MOS transistor, and the gate of the MOS transistor is connected to the reference MOS half. The gate of the transistor, the source of the MOS transistor of the detecting unit is connected to the source of the reference MOS transistor, and the MOSFET of the detecting unit is extremely close to the detecting end. 5. The current detecting device of claim 4, wherein the detecting device JJ1 still has a current mirror. One of the current mirrors refers to the drain of the oxygen half transistor. One of the mirror ends of the current mirror generates a proportional mirror current according to the detected current. 6. The current sensing device of claim 4, wherein the 4 measuring unit further comprises a level adjusting unit coupled to the gold oxygen half of the measuring element Between the transistor> and the drain of the reference MOS transistor, the voltage level of the drain of the MOS transistor is approximately equal to that of the reference MOS transistor. 7. The current detecting device of claim 2, wherein the balancing current unit comprises a reference bipolar junction type transistor and at least one output bipolar port. a combined transistor, wherein a base of the reference bipolar junction transistor is coupled to a base of the at least one output bipolar junction transistor, and an emitter of the reference bipolar junction transistor and the at least one An emitter connection of the output bipolar junction type transistor, one of the reference bipolar junction type transistors is coupled to the reference terminal and coupled to the base of the reference bipolar junction type transistor, the at least one output bipolar junction The set of type transistors is at least one output. 8. The current detecting device of claim 7, wherein the detecting unit comprises a bipolar junction type transistor, and a base of the detecting unit of the bipolar junction type transistor is connected to the reference pair a base of the pole-joining transistor, the emitter of the bipolar junction type transistor of the detecting unit is connected to the emitter of the reference bipolar junction type transistor, and the set of the bipolar junction type transistor of the detecting unit is extremely The detection end. 19 153 153 9. The current detecting device measuring unit according to claim 8 further comprising a current mirror, wherein a reference end of the current mirror is coupled to the collector of the bipolar junction type transistor, and one of the current mirrors is mirrored The terminal generates a proportional image current according to the detected current. 10. The current detecting device of claim 8, wherein the detecting unit further comprises a level adjusting unit coupled to the bipolar junction type transistor of the detecting unit Between the collector and the collector of the reference bipolar-junction transistor, the voltage level of the collector of the bipolar junction type/transistor of the detection unit is approximately equal to the reference bipolar junction type: transistor The voltage level of the collector. A DC output circuit having a current detecting device, comprising: a converting circuit coupled to an input voltage, and converting the input voltage into a DC output voltage according to a control signal; and a current detecting device comprising a current mirror generates a current detecting signal according to a load current flowing through the load, wherein the current mirror includes a first common end, a first reference end, and at least a first mirror end, wherein the Φ is at least a first One of the mirroring ends is a detecting end, and the controller is coupled to the controller and the image is generated by the equal-magnitude mirroring to generate the current detecting signal. The first reference end and the other end of the at least one first mirroring end are coupled to the The load is coupled to the load current, the first common terminal is coupled to a first reference level; and a controller is coupled to and driven by the driving voltage and the ground, and the controller is coupled to the conversion circuit And the current mirror, and generating the control signal according to the current detection signal to adjust the magnitude of the load current of 20 M339153. The DC output circuit of claim 11, wherein the first reference terminal and the other first mirror ends coupled to the load pass approximately the same current. 13. The DC output circuit of claim 11, further comprising a resistor, one end of the resistor coupled to the detecting end and the other end connected to the driving voltage or ground. The DC output circuit of claim 11, further comprising a second current mirror comprising a second common end, a second reference end and a second mirror end, wherein the second reference end is coupled In the detecting end, the second mirroring end is coupled to the controller and generates a mirroring detection current according to the current detecting signal, and the second common terminal is coupled to a second reference level. 15. The DC output circuit of claim 14, wherein the second reference level is a level of the driving voltage. 16. The DC output circuit of claim 11, wherein the first common terminal is coupled to ground. The DC output circuit of claim 16, further comprising a resistor coupled between the driving voltage and the detecting end, wherein a current flowing through the detecting end flows through the resistor The current detection signal is generated. 18. The DC output circuit of claim 16, further comprising a resistor coupled to the detecting end and coupled to the ground, wherein a current flowing through the detecting end flows through the resistor to generate the current Detection signal. 19. The DC output circuit of claim 11, wherein the DC output voltage is a negative voltage, and the first common terminal is coupled to ground. 21 M339153 The DC output circuit described in claim 11 wherein the output voltage is a negative voltage, and the first common terminal is coupled to the DC output voltage. 21. The DC output circuit of claim 20, wherein the first reference level is a level of the DC output voltage. 22. The DC output circuit of claim 21, further comprising a second current mirror comprising a second common end, a second reference end, and a second mirror end coupled to the second reference end In the detecting end, the second mirroring end is coupled to the controller and generates a mirroring detection current according to the current detecting signal, and the second common terminal is coupled to a second reference level. The bit is below the grounding level. 23. The DC output circuit of claim 20, further comprising a resistor coupled between the driving voltage and the detecting end, wherein a current flowing through the detecting end flows through the resistor The current detection signal is generated. twenty two