TWI431914B - A boost converter with positive and negative outputs - Google Patents

Description

Boost converter with positive and negative outputs

The present invention relates to a boost converter, and more particularly to a boost converter having positive and negative outputs.

Many applications require positive and negative voltage supply with regulated output. For example, the vehicle power generated by the engine-driven generator charging 12V lead-acid battery can supply in-vehicle electronic devices, including engine control systems, audio and other entertainment equipment. . However, electronic devices that use automotive power supplies are subject to excessive changes in input voltage. For example, when the vehicle power supply is about to run out, the vehicle battery voltage will be reduced to 10V, or when the vehicle battery cable is loose or broken. The front-end voltage regulator circuit will output a voltage of up to 16V to the circuit at the back end.

Since the voltage of the vehicle battery varies with the engine speed, the normal operating voltage of 12V, when applied to the acoustic amplifier designed by the half-bridge drive architecture, can only be obtained on the commonly used 4 ohm speaker load. The output power of W, which is obviously insufficient. Therefore, it is necessary to operate the amplifier at a higher voltage, and in order to provide a better low frequency response output, it is preferable to use a positive and negative voltage supply so that the half bridge driven class D amplifier can omit the DC blocking capacitor.

There are many previous research literatures on circuits that convert single-supply to positive and negative outputs, such as the paper "Double output Luo-converters-voltage lift technique" by Luo, FL, but the circuit The architecture is complex and there are many components. Then there is a simpler architecture, but the negative output capacitor voltage will be unbalanced. problem.

Accordingly, it is an object of the present invention to provide a boost converter having a positive and negative output that is easy to implement with a circuit.

Therefore, the boost converter of the present invention having positive and negative outputs includes a switching element, an inductor, a positive voltage output circuit and a negative voltage output circuit.

The switching element has a first end electrically connected to the power source and a second end; the inductor has a grounded first end and a second end electrically connected to the second end of the switching element.

The positive voltage output circuit is electrically connected between the second end of the inductor and the positive output end, and has: a first capacitor having a first end electrically connected to the second end of the inductor and a second end; a conducting component having a first end electrically connected to the second end of the first capacitor and a second end connected to the ground; a second conducting component having a first end electrically connected to the first end of the first conducting component a first end and a second end electrically connected to the positive output end; and a second capacitor having a first end electrically connected to the second end of the second conducting element and the positive output end The second end of the ground.

The negative voltage output circuit is electrically connected between the second end of the inductor and the negative output end, and has a third capacitor having a first end and a second end electrically connected to the second end of the inductor; The conducting component has a first end electrically connected to the second end of the third capacitor and a second end connected to the ground; a fourth conducting component having a first electrical connection with the first end of the third conducting component And a fourth capacitor having a first end electrically connected to the second end of the fourth conducting component and the positive end And a grounded second end.

Thereby, when the switching element is turned on or off, the first capacitor and the second capacitor of the positive voltage output circuit and the third capacitor and the fourth capacitor of the negative voltage output circuit respectively supply current to the inductor to make the inductor Magnetically boosts the positive output and the negative output.

The technical feature of the present invention is that when the switching element is turned on or off, the positive voltage output circuit and the negative voltage output circuit supply current to the inductor to excite the inductor and boost the positive and negative outputs. It can be used by electronic devices that supply positive and negative voltage supply sources that require regulated output.

The foregoing and other objects, features, and advantages of the invention are set forth in the <RTIgt;

Referring to FIG. 1, in a preferred embodiment of the present invention, the boost converter 100 includes a switching element Q ₁ , an inductor L ₁ , a positive voltage output circuit 101 , a negative voltage output circuit 102 , and a positive output terminal 61 . 62, and a negative output terminal; wherein the switching element Q ₁ has a power source 60 is electrically connected to a first end 11 and a second end 12; a first inductor L ₁ having a grounded terminal 21 and a switching element Q ₁ the second ends of the electrical connector 2212; the positive voltage output circuit 101 is electrically connected to a second end of the inductor L ₂₂₁ and the positive output terminal 61, the negative voltage output circuit electrically connected to the second inductor L ₁ Between the end 22 and the negative output 62.

The technical feature of the present invention is that the inductor L ₁ has a function similar to a boost (Boost-Boost), and is matched with the capacitance of the positive voltage output circuit 101 and the negative voltage output circuit 102 to achieve positive and negative boost output, regardless of the switching element Q. when _a conducting or non-conducting, a positive voltage output circuit 101 and the negative voltage output circuit 102 are supplied to the inductor L ₁ the inductance L ₁ magnetizing current thus rendering the output terminal 61 and the negative boost output terminal 62, and therefore needs to be supplied with It is used by electronic devices with positive and negative voltage supply sources for regulated output.

The detailed circuit of the preferred embodiment is described below.

A first diode 11 and a second terminal 12 of the switching element Q ₁ are oppositely connected to a diode D _{b 1} , the switching element Q ₁ is an N-type gold-oxygen half field effect transistor, and the first terminal 11 is a source, The two ends 12 are bungee poles, and their gates are controlled to determine whether they are turned on or not.

The positive voltage output circuit 101 has a first capacitor C ₁ , a first conducting component D ₁ , a second conducting component D _{2 ,} and a second capacitor C ₃ .

The first capacitor C ₁ has a first end 311 and a second end 312 electrically connected to the second end 22 of the inductor L ₁ . The first conductive element D ₁ has a first connection to the second end 312 of the first capacitor C ₁ . The first end 331 and the grounded second end 332, the second conductive element D ₂ has a first end 321 electrically connected to the first end 331 of the first conductive element D ₁ and an electrical connection positive output end 61 The second end 322, the second capacitor C ₃ has a first end 341 electrically connected between the second end 322 of the second conducting element D ₂ and the positive output end 61 and a grounded second end 342; The first capacitor C ₁ and the second capacitor C ₃ are responsible for providing the boosting energy of the positive output terminal 61.

The negative voltage output circuit 102 has a third capacitor C ₂ , a third conduction component D ₃ , a fourth conduction component D _{4 ,} and a fourth capacitor C ₄ .

The third capacitor C ₂ has a first end 511 and a second end 512 electrically connected to the second end 22 of the inductor L ₁ , and the third conductive element D ₃ has a second end 512 electrically connected to the third capacitor C ₂ . The first end 531 and the grounded second end 532, the fourth conductive element D ₄ has a first end 521 electrically connected to the first end 531 of the third conductive element D ₃ and an electrically connected negative output end 62 The second end 522, the fourth capacitor C ₄ has a first end 541 electrically connected between the second end 522 and the negative output end of the fourth conducting element D ₄ and a grounded second end 542; The third capacitor C ₂ and the fourth capacitor C ₄ are responsible for providing the boosting energy of the negative output terminal 62.

2 and FIG. 3 are waveform diagrams of analog current and voltage timing of each element, and FIG. 4 is a current flow direction of the switching element Q ₁ during the period t ₀ to t ₁ (hereinafter referred to as the first mode), and FIG. 5 is The non-conduction period of the switching element Q ₁ is the current flow of the time t ₁ to t ₂ (hereinafter referred to as the second mode), and the operation principle of each element of the preferred embodiment will be described below.

A first pattern: refer to FIG. 4, the switching element Q ₁ turns on (time t ₀ to t _1), the inductance L ₁ magnetizing make I _{L 1} current rise, while the third conductive element D ₃ due to forward bias is turned on, the third The capacitor C ₂ is charged to the input voltage V _in ; furthermore, since the negative terminal of the first capacitor C ₁ is boosted to the input voltage V _in to provide boosting energy, the second conducting element D ₂ is turned on, so the positive output The positive output voltage V _{o 1} = V _{C 3} = V _{C 1} + V _in , the energy of the negative output terminal 62 is the boosting energy provided by the fourth capacitor C ₄ , so the negative output voltage V _{0 of the} negative output terminal 62 ₂ = V _{C 4} .

Second mode: FIG. 5, the switching element Q ₁ nonconducting (times t ₁ to t _2), the inductance L ₁ so that the exciting current I _{L 1} rises, while the inductance L ₁ connected in series the voltage across the third capacitor C ₂ to the first The four capacitor C _{4 is} charged. At this time, the voltage V _{o 1 of the} positive output terminal 61 is supplied with the boosting energy by the second capacitor C ₃ , so the positive output voltage V _{o 1 of the} positive output terminal 61 is V _{C 3} and the negative output terminal 62 The voltage V _{o 2} = V _{C 4} = - ( V _{C 2} + V _{L 1} ), and since the inductor L ₁ also charges the first capacitor C ₁ to provide boosting energy, the voltage of the inductor L ₁ is V _{L 1} = - V _{C 1} , thus the negative output voltage V _{o 2} of the negative output 62 = -( V _{C 2} + V _{C 1} ).

Suppose C ₁ has been charged to V _{C 1,} the inductor L ₁ by the volt-second balance (volt-second balance) principle that _{D × V in = (1- D} ) × V C 1, and therefore,

In the first mode,

And V _{o 1} = V _{C 4} Equation 3

In the second mode, since the voltage across the second capacitor C ₃ is still stabilized by the voltage represented by Equation 2,

And V _{o 2} =-( V _{C 1} - V _{L 1} )=-( V _{C 1} -(- V _{C 2} ))=-( V _{C 1} + V _{C 2} ) Formula 5

Since C ₂ is quickly charged to the input voltage V _in when it is in the first mode, Equation 5 can be rewritten as

and

The experimental conditions of the preferred embodiment are: (i) the DC input voltage V _in is 10 to 16 volts; (ii) the proportional output voltage V _{o 1} is +25 volts and V _o2 is -25 volts; (iii) The proportional output current I _c4 is 1.25 amps; (iv) the equal-ratio output power is 62.5 watts; (v) the switching frequency is 200 kHz; (vi) the capacitance values of the first capacitor C ₁ and the third capacitor C ₂ are 22 μF; (vii The capacitance values of the second capacitor C ₃ and the fourth capacitor C ₄ are 330 μF; (viii) the type of the switching element Q ₁ is IRF 540 NS; and (ix) the first conduction element D ₁ , the second conduction element D ₂ , and the third The type of the conduction element D ₃ and the fourth conduction element D ₄ is MS22.

Referring to FIG. 6 and FIG. 7, for the circuit architecture using the foregoing components, current and voltage timing waveforms actually measured corresponding to different components of FIG. 2 are provided when the input voltage V _in is 10 volts.

Referring to FIG. 8, FIG. 9, and FIG. 10, FIG. 8 is a waveform of voltages V _gs , V _ds , V _{d1 ,} and V _d2 generated when the input voltage V _in is 10 volts; FIG. 9 is an input voltage V _in 12 volts. Waveforms of the generated voltages V _gs , V _ds , V _{d1 ,} and V _d2 ; FIG. 10 is a waveform of voltages V _gs , V _ds , V _{d1 ,} and V _d2 generated at an input voltage V _in of 16 volts.

Referring to FIG. 11, 12 and 13, respectively, the input voltage V _in is 10 volts, 12 volts and 16 volts, and the figures are indicative of the switching element Q gate-driver signal (gate driving signal) of the _voltage V _gs The timing waveforms of the voltages V _c1 and V _{c2 of the} inductor current I _L1 , the first capacitor C ₁ and the third capacitor C ₂ .

As can be seen from FIG. 2 and the timing waveform diagram described above, a single positive voltage power supply can obtain a stable boost output at the positive output terminal 61 and the negative output terminal 62, respectively. Further, referring to FIG. 14, regardless of the load percentage, The conversion efficiency (Efficiency) at input voltages of 10 volts, 12 volts, 14 volts, and 16 volts is above 91.8%.

In summary, the present invention has the advantages that only a single power supply input voltage V _in can obtain a boosted positive output voltage V _{o 1} and a negative output voltage V _o2 , can be applied to a class D amplifier, and the circuit is easy. It is achieved that the object of the invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

100‧‧‧Boost converter

101‧‧‧ positive voltage output circuit

102‧‧‧Negative voltage output circuit

11, 21, 311, 321, 331, 341, 511, 521, 531, 541‧‧‧ first end

12, 22, 312, 322, 332, 342, 512, 522, 532, 542‧‧ second end

60‧‧‧Power supply

61‧‧‧ positive output

62‧‧‧negative output

C ₁ ‧‧‧first capacitor

C ₃ ‧‧‧second capacitor

C ₂ ‧‧‧ third capacitor

C ₄ ‧‧‧fourth capacitor

D ₁ ‧‧‧First conduction element

D ₂ ‧‧‧second conduction element

D ₃ ‧‧‧third conduction element

D ₄ ‧‧‧fourth conducting component

D _{b 1} ‧‧‧ diode

L ₁ ‧‧‧Inductance

Q ₁ ‧‧‧Switching elements

V _{o 1} ‧‧‧ positive output voltage

V _{o 2} ‧‧‧negative output voltage

1 is a circuit diagram showing a preferred embodiment of the boost converter of the present invention; FIG. 2 is a timing waveform diagram illustrating the analog current and voltage waveforms of a portion of the components of FIG. 1; FIG. 3 is a timing waveform diagram illustrating FIG. 4 is a circuit diagram illustrating the current flow of the switching element of FIG. 1; FIG. 5 is a circuit diagram illustrating the non-conducting current flow of the switching element of FIG. 1; FIG. Is a timing waveform diagram illustrating the current and voltage waveforms actually measured by a part of the components of FIG. 1; FIG. 7 is a timing waveform diagram illustrating current and voltage waveforms actually measured by another component of FIG. 1; FIG. A waveform diagram illustrating waveforms of voltages V _gs , V _ds , V _{d1 ,} and V _d2 at an input voltage of 10 volts; and FIG. 9 is a timing waveform diagram illustrating voltages V _gs , V _ds at an input voltage of 12 volts , waveforms of V _d1 and V _d2 ; FIG. 10 is a timing waveform diagram illustrating waveforms of voltages V _gs , V _ds , V _{d1 ,} and V _d2 at an input voltage of 16 volts; FIG. 11 is a timing waveform diagram illustrating Gate level of a switching element with an input voltage of 10 volts The voltage waveform of the driving signal, the inductor current, the first capacitor and the third capacitor; FIG. 12 is a timing waveform diagram illustrating the voltage, the inductor current, and the first capacitor of the gate driving signal of the switching element having an input voltage of 12 volts. And a voltage waveform of the third capacitor; FIG. 13 is a timing waveform diagram illustrating voltages of the gate driving signals, the inductor current, the first capacitor, and the third capacitor of the switching element having an input voltage of 16 volts; and FIG. It is a waveform diagram illustrating the conversion efficiency at different output voltages for different load rates.

100‧‧‧Boost converter

101‧‧‧ positive voltage output circuit

102‧‧‧Negative voltage output circuit

11, 21, 311, 321, 331, First end of 341, 511, 521, 531, 541‧‧

12, 22, 312, 322, 332, 342, 512, 522, 532, 542‧‧ second end

60‧‧‧Power supply

61‧‧‧ positive output

62‧‧‧negative output

C ₁ ‧‧‧first capacitor

C ₃ ‧‧‧second capacitor

C ₂ ‧‧‧ third capacitor

C ₄ ‧‧‧fourth capacitor

D ₁ ‧‧‧First conduction element

D ₂ ‧‧‧second conduction element

D ₃ ‧‧‧third conduction element

D ₄ ‧‧‧fourth conducting component

D _{b 1} ‧‧‧ diode

L ₁ ‧‧‧Inductance

Q ₁ ‧‧‧Switching elements

V _{o 1} ‧‧‧ positive output voltage

V _{o 2} ‧‧‧negative output voltage

Claims (2)

A step-up converter having positive and negative outputs, comprising: a switching element having a first end and a second end receiving an input voltage; an inductor having a grounded first end and a switching element a second end electrically connected to the second end; a positive voltage output circuit electrically connected between the second end of the inductor and the positive output end, having: a first capacitor having a second end electrically connected to the inductor The first end and the second end, a first conducting component having a first end electrically connected to the second end of the first capacitor and a second grounding end, and a second conducting component having a a first end electrically connected to the first end of the first conductive element and a second end electrically connected to the positive output end, and a second capacitor having a second end electrically connected to the second conductive element a first end between the positive output end and a grounded second end; and a negative voltage output circuit electrically connected between the second end of the inductor and the negative output end, having: a third capacitor having a Electrically connecting the first end of the second end of the inductor and a second end, a third lead Element having a first end and a second end connected to a ground of the second end of the third capacitor, a fourth conductive member having a first and the third conductive element a first end of the electrical connection and a second end electrically connected to the negative output, and a fourth capacitor having a second electrical connection between the second end of the fourth conductive component and the positive output a first end and a grounded second end; wherein, when the switching element is turned on or off, the first capacitor and the second capacitor of the positive voltage output circuit and the third capacitor and the fourth capacitor of the negative voltage output circuit are both A current is supplied to the inductor to excite the inductor to boost the positive output and the negative output. A step-up converter having a positive and negative output according to claim 1, wherein a first diode and a second terminal of the switching element are connected in reverse with a diode, and the switching element is N. The type of gold-oxygen half-field effect transistor has a first end as a source and a second end as a drain, and its gate is controlled to determine whether it is conducting or not.