CN201146470Y

CN201146470Y - Current changer regulating voltage in preceding stage

Info

Publication number: CN201146470Y
Application number: CNU2008200004356U
Authority: CN
Inventors: 梁适安; 李国辉; 许根川
Original assignee: FSP Technology Inc
Current assignee: FSP Technology Inc
Priority date: 2008-01-11
Filing date: 2008-01-11
Publication date: 2008-11-05
Anticipated expiration: 2018-01-11

Abstract

The utility model relates to a pre-stage voltage regulating current converter, which comprises a pre-stage voltage regulating unit, a work cycle modulation unit, a half-bridge driving unit and a voltage transformation unit, wherein, the pre-stage voltage regulating unit obtains an input power by connection, and the pre-stage voltage regulating unit obtains a dimming signal and a feedback signal; the voltage of the input power is regulated by the pre-stage voltage regulating unit according to the dimming signal, and feedback adjustment is performed according to the feedback signal; the periodic signal generated by the work cycle modulation unit can not change in accordance with the dimming signal and the feedback signal, and the half-bridge driving unit always working under zero-voltage switching status drives the voltage transformation unit to output a driving power. The pre-stage voltage regulating converter has the advantages that switching loss is reduced; the service life of circuit elements and loads are prolonged; the drawback of loss increasing as the existing converter cannot be fixed under zero-voltage switching status is improved.

Description

The converter of prime pressure regulation

Technical field

The utility model relates to a kind of converter of prime pressure regulation, particularly relates to a kind of semi-bridge converter device that drives module backlight.

Background technology

LCD has been popularized in various electronic goods and has been known by common people now, the performance of this LCD and usefulness are except the good and bad institute that is subjected to liquid crystal module influences, the stability of module backlight is very important also, and module backlight comprises a light tube group and a converter (inverter), and this converter must provide the stable electric current of light tube group and have the ability of long-time steady operation; The basic principle of converter is to obtain direct current electric power input to utilize electronics to switch pattern to switch the flow through direction of a transformer primary side of this direct current power, make secondary side conversion output one alternating electromotive force of this transformer, in other words, converter is that direct current power is converted to alternating electromotive force to drive the AC load as cold cathode fluorescent lamp (CCFL) and so on, and converter roughly is divided into the Royer formula, full-bridge type, semibridge system and push-pull type, wherein the Royer formula is the self-oscillation design, be subjected to the influence of component parameters deviation, be difficult to strict control lamp frequency and lamp current, drive controlling accurately, and the employed power transistor of push-pull type converter must be able to bear the input voltage of twice, thereby the cost of power transistor is higher and have a restriction for input voltage, more general is full-bridge type or semi-bridge converter device, and the semi-bridge converter device is comparatively simple and the power transistor that uses half of full-bridge type more, is lower-cost selection; Knownly see also Fig. 1 in order to the converter framework that drives module backlight, this converter comprises that connection one obtains input electric power and rectification is the rectification unit 40 of direct current power, the work period modulation unit 42 and the power factor correction function unit 41 that connect this rectification unit 40, one half-bridge driver element 43, an and voltage transformation unit 44, and for reaching the effect of stable output, the secondary side of this voltage transformation unit 44 connects back coupling unit 45 generations one feedback signal and delivers to this work period modulation unit 42, this power factor correction function unit 41 is obtained an input electric power and is adjusted the phase difference of its electric current and voltage from this rectification unit 40, and should obtain a dim signal and obtain this feedback signal in 42 connections, one dim signal source 3, work period modulation unit, and produce the responsibility cycle (duty cycle) of one-period this half bridge drive unit 43 of signal deciding according to this dim signal and this feedback signal, drive at least one load 2 thereby adjust half bridge drive unit 43 conductings this input flow of power produces an interchange through the sequential of this voltage transformation unit 44 driving electric; Above-mentioned half bridge drive unit 43 utilizes the keying of power switch component to reach the effect that changes the conducting sequential, in order to reach zero voltage switching to reduce the loss at power switch component two ends, the semi-bridge converter device must limit its responsibility cycle (duty cycle) to meet the condition of zero voltage switching, yet known converter is in order to provide stable output to drive this load 2, the responsibility cycle (duty cycle) that a feedback signal changes this semi-bridge converter device certainly will will be produced, thereby most time of this semi-bridge converter phase can't be worked under the state of zero voltage switching, make the efficient of real work be lower than perfect condition, such previous utility model such as TaiWan, China patent announcement I273764 number, I242177 number, No. the 6995989th, No. 518633 and United States Patent (USP); And, the converter of known drive module backlight mostly adopts low-frequency pulse formula light modulation (burst mode dimming), the action that this kind mode makes the fluorescent tube repeated priming, extinguishes, though can obtain good dimming characteristic, but, the converter power supply changes because of being pulsed, can make the transformer that the input power supply of electric power and this converter are provided produce low frequency noise, cause the discomfort of human body, also can produce problems such as reduction of circuit element and lamp tube service life and electromagnetic interference (EMI) be more serious.

The utility model content

In view of known semi-bridge converter utensil has above-mentioned defective, thereby the purpose of this utility model promptly is to provide a kind of semi-bridge converter device of improvement, to improve the defective that above-mentioned efficient is lower and lamp tube service life is short.

Via as can be known above, for achieving the above object, the utility model is a kind of converter of prime pressure regulation, this converter comprises rectification unit, the power factor correction function unit, work period modulation unit, half bridge drive unit, voltage transformation unit and prime pressure regulation unit, wherein this rectification unit is obtained input electric power, and this prime pressure regulation unit is delivered in rectification, and this prime pressure regulation unit connects the dim signal source to obtain dim signal, and feedback signal is also obtained from this voltage transformation unit secondary side in this prime pressure regulation unit, make this prime pressure regulation unit should change the voltage of this input electric power according to the size decision pressure regulation position standard of this dim signal, and feedback adjustment with this feedback signal, control this half bridge drive unit and under fixing responsibility cycle, work and should work period modulation unit should produce fixing periodic signal, to change the driving electric voltage that this voltage transformation unit is converted to secondary side, make the secondary side of this voltage transformation unit be exported driving electric and drive at least one load; Because this dim signal and this feedback signal change the output of this converter by the voltage of controlling this prime pressure regulation unit and adjusting this input electric power in advance, but this half bridge drive unit steady job, and need not used the mode of low-frequency pulse formula light modulation and prolongs the life-span of circuit element and load reducing handoff loss in the state of zero voltage switching.

Description of drawings

Fig. 1 is the framework calcspar of known converters.

Fig. 2 is the preferred embodiment framework calcspar of the utility model.

Fig. 3 preferably implements the framework calcspar for prime pressure regulation of the present utility model unit.

Embodiment

Relevant detailed description of the present utility model and technology contents now just cooperate schematic view illustrating as follows:

The preferred embodiment of the utility model sees also Fig. 2, the utility model is a kind of converter of prime pressure regulation, obtain an input electric power and be converted to a driving electric to drive at least one load 2, this converter comprises a rectification unit 40, one work period modulation unit 42, an one half-bridge driver element 43 and a voltage transformation unit 44, and establish a prime pressure regulation unit 46 between this half bridge drive unit 43 and this rectification unit 40, it is direct current that this rectification unit 40 should be imported power conversions, this input electric power is obtained from this rectification unit 40 in this prime pressure regulation unit 46, and this prime

pressure regulation unit

46 and 40 of this rectification units also comprise the current phase of a power factor correction function unit 41 these input electric power of adjustment, this prime pressure regulation unit 46 connects a dim signal source 3 and obtains a dim signal, and determine a pressure regulation position standard according to this dim signal, and according to the accurate input voltage of power that changes these half bridge drive unit 43 conductings to this voltage transformation unit 44 in this pressure regulation position, this work period modulation unit 42 produces the one-period signal after this rectification unit 40 is obtained this input power start, this periodic signal drives the direction of this this input flow of power of half bridge drive unit 43 conductings through voltage transformation unit 44, thereby driving this voltage transformation unit 44 these input electric power of conversion forms a driving electric and drives at least one load 2, and the secondary side of this voltage transformation unit 44 also connects one and feedbacks unit 45 producing a feedback signal, and this prime pressure regulation unit 46 should be adjusted the voltage of this input electric power and stablize the voltage of this driving electric according to the size of this feedback signal; By above-mentioned framework, this dim signal and this feedback signal are adjusted the voltage of this input electric power by this prime pressure regulation unit 46, and then change the size of this driving electric, therefore the periodic signal that should work period modulation unit 42 produces does not need to change with this dim signal and this feedback signal, makes this half bridge drive unit 43 can keep fixing responsibility cycle (duty cycle) and reaches the effect that works in the zero voltage switching state.

See also Fig. 3, this figure is depicted as one of this prime pressure regulation unit 46 and implements framework, wherein this prime pressure regulation unit 46 comprises a voltage-dropping type (BUCK) circuit 461 and a voltage regulator control circuit 462, this input electric power is delivered to this voltage-dropping type (BUCK) circuit 461 through this power factor correction function unit 41, and this voltage regulator control circuit 462 connects this dim signal source 3 and should feedback unit 45, produce one by this dim signal and this feedback signal and open and close the responsibility cycle that periodic signal is controlled 461 switchings of this voltage-dropping type (BUCK) circuit, thereby make this voltage-dropping type (BUCK) circuit 461 comply with the voltage that its responsibility cycle is adjusted this input electric power, 43 of this half bridge drive unit are complied with its fixing periodic signal conducting should import flow of power through this voltage transformation unit 44; By above-mentioned framework, the utility model can be fixed the state down work of this half bridge drive unit 43 in zero voltage switching, and, can reach and reduce handoff loss, the effect in prolongation electronic component life-span not because of the change of this load 2 or this dim signal changes responsibility cycle.

Above-mentioned voltage regulator control circuit 462 is an integrated circuit; and this load 2 is a light tube group; this half bridge drive unit 43 can be asymmetrical half-bridge formula (AsymmetricalHalf-Bridge) power-switching circuit; though the utility model discloses as above with preferred embodiment; yet it is not in order to limit the utility model; any those skilled in the art; in not breaking away from spirit and scope of the present utility model; and a little change and the retouching done; all should be covered by in the utility model, therefore protection range of the present utility model is as the criterion when looking accompanying the claim person of defining.

Claims

1. the converter of a prime pressure regulation, obtain input electric power and be converted to driving electric to drive at least one load (2), described converter comprises the rectification unit (40) of obtaining described input electric power and rectification, produce the work period modulation unit (42) of periodic signal, the half bridge drive unit (43) that driven by described periodic signal, and drive and change the voltage transformation unit (44) that described input electric power forms described driving electric by described half bridge drive unit (43), and dim signal is obtained in described converter connection dim signal source (3), it is characterized in that described converter also comprises:

Prime pressure regulation unit (46), be connected between described rectification unit (40) and the described half bridge drive unit (43), described prime pressure regulation unit (46) is obtained described input electric power and should be determined pressure regulation position standard by the size of described dim signal, and according to the accurate input voltage of power that changes described half bridge drive unit (43) conducting to described voltage transformation unit (44) in described pressure regulation position, to adjust the driving electric voltage that described voltage transformation unit (44) is converted to secondary side.

2. the converter of prime pressure regulation according to claim 1, it is characterized in that, described prime pressure regulation unit (46) comprises voltage-dropping type circuit (461) and voltage regulator control circuit (462), and wherein said voltage regulator control circuit (462) receives described feedback signal and described dim signal opens and closes the responsibility cycle that periodic signal is controlled described voltage-dropping type circuit (461) switching to produce.

3. the converter of prime pressure regulation according to claim 2 is characterized in that, described voltage regulator control circuit (462) is an integrated circuit.

4. the converter of prime pressure regulation according to claim 1, it is characterized in that, the secondary side of described voltage transformation unit (44) also connects feedbacks unit (45) producing feedback signal, and described prime pressure regulation unit (46) should be adjusted the voltage of described input electric power and stablize the voltage of described driving electric according to the size of described feedback signal.

5. the converter of prime pressure regulation according to claim 1 is characterized in that, described load (2) is a light tube group.

6. the converter of prime pressure regulation according to claim 1 is characterized in that, also comprises the current phase of the described input electric power of power factor correction function unit (41) adjustment between described prime pressure regulation unit (46) and the described rectification unit (40).

7. the converter of prime pressure regulation according to claim 1 is characterized in that, described half bridge drive unit (43) can be asymmetrical half-bridge formula power-switching circuit.