CN206364698U - It is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response - Google Patents
It is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response Download PDFInfo
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- CN206364698U CN206364698U CN201621448922.XU CN201621448922U CN206364698U CN 206364698 U CN206364698 U CN 206364698U CN 201621448922 U CN201621448922 U CN 201621448922U CN 206364698 U CN206364698 U CN 206364698U
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- electric capacity
- compensating electric
- clamper
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Abstract
The utility model offer is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response, for carrying out clamper to the external compensating electric capacity of LED drive chip, module is enabled including a compensating electric capacity charging module, a compensating electric capacity clamper module and a clamper, the clamper enables module and carries out clamper to the voltage of the compensating electric capacity according to a switch maximum ON time signal enable compensating electric capacity clamper module.The utility model can be adaptively by the voltage clamping of compensating electric capacity in the compensating electric capacity voltage corresponding to the maximum ON time of switch, so as on the premise of compensating electric capacity normal working voltage scope is not influenceed, reduce the time needed for loop response adjustment of the circuit from compensating electric capacity clamping state to stable state as far as possible, it is to avoid output is in overshoot state for a long time.
Description
Technical field
The utility model is related to LED drive circuit field, more particularly to one kind improves quick power-on and power-off loop response repeatedly
Compensating electric capacity clamp circuit.
Background technology
Existing High Power Factor LED drive chip typically can connect compensating electric capacity in chip exterior when in use, for
Produce the ON time of the low-frequency d voltage and control chip output switch relative to AC frequencies.During steady operation, compensation electricity
Steady state voltage in appearance is determined by the application conditions such as load and input voltage.Voltage in the more low then compensating electric capacity of input voltage is more
Height, so that the ON time of chip output switch increases to maintain the constant current effect of output LED load.When driving chip is in reality
Border application in repeatedly quick power-on and power-off when, because input voltage reduces rapidly, the voltage in compensating electric capacity is lifted.Afterwards in core
Piece supply voltage is not dropped to also before under-voltage locking point and fast powering-up, now because the voltage in compensating electric capacity has been elevated,
Output will appear from overshoot.Such repeatedly quick power-on and power-off will cause compensating electric capacity too high, and output is overshooted, until loop response
Slowly it is adjusted to stable state.
In this regard, this area devises compensating electric capacity clamp circuit as shown in Figure 1.In the circuit, transconductance modulator GM ' roots
Reference voltage vref1 ' and chip output current feedback signal Io_fb ' adjustment compensating electric capacities the Ccomp ' set according to chip internal
Voltage comp '；Hysteresis comparator is compared the voltage comp ' on current compensating electric capacity Ccomp ' with a reference voltage vref ',
And export clamp signal clamp '.When comp ' is higher than vref ', clamp ' is high level, drives metal-oxide-semiconductor M1 ' conductings, drop-down
Compensating electric capacity Ccomp '；When comp ' is less than vref ', clamp ' is low level, drives M1 ' shut-offs, is mended by GM ' adjust automaticallies
Repay the voltage comp ' on electric capacity Ccomp '.
It can be seen that, existing compensating electric capacity clamp circuit is by the voltage comp ' clampers on compensating electric capacity Ccomp ' in benchmark electricity
Press vref ' places.The reference voltage vref ' if set it is too low if influence normal work when compensating electric capacity Ccomp ' voltage model
Enclose.In order to not influence voltage range during compensating electric capacity Ccomp ' normal works, often by reference voltage vref ' set compared with
Height, however, if set it is too high if circuit can be made to be adjusted to stable state through loop response from compensating electric capacity clamping state taken
Between it is long, cause chip output for a long time be in overshoot state.
Utility model content
For above-mentioned the deficiencies in the prior art, the utility model, which is provided, a kind of improves repeatedly quick power-on and power-off loop response
Compensating electric capacity clamp circuit, it can be adaptively by the voltage clamping of compensating electric capacity in the benefit corresponding to the maximum ON time of switch
Capacitance voltage is repaid, so as on the premise of compensating electric capacity normal working voltage scope is not influenceed, reduce from compensating electric capacity pincers as far as possible
Time needed for position state to the loop response adjustment of stable state, it is to avoid output is in overshoot state for a long time.
To achieve these goals, the utility model is adopted the following technical scheme that：
It is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response, outside to LED drive chip
The compensating electric capacity connect carries out clamper, including a compensating electric capacity charging module, a compensating electric capacity clamper module and a clamper enable mould
Block, the clamper enables module and enables the compensating electric capacity clamper module to the benefit according to the maximum ON time signal of a switch
The voltage for repaying electric capacity carries out clamper.
Further, the clamper enables module and included：
One current source, its input connects a power supply；
One slope electric capacity, its positive plate connects the output end of the current source, negative pole plate earthing；
One slope electric capacity resets NMOS tube, the positive plate of its connection slope electric capacity that drains, source ground, grid connection
One chip output switch cut-off signals end；
One comparator, its positive input connects the positive plate of the slope electric capacity, and negative input connects the compensation
The positive plate of electric capacity；
One nor gate, its first input end connects the output end of the comparator, and the switch of the second input connection one is maximum
ON time signal end, to receive the maximum ON time signal of the switch；And
One rest-set flip-flop, its set end connects the output end of the nor gate, and reset terminal connects a chip output switch and led
Messenger end, output end connects the compensating electric capacity clamper module.
Further, the compensating electric capacity charging module includes a transconductance modulator, and its positive input terminal connects a reference voltage
End, negative input end connects a chip output current feedback end, and output end connects the positive plate of the compensating electric capacity.
Further, the compensating electric capacity clamper module includes a clamper NMOS tube and a clamper current-limiting resistance, the pincers
The drain electrode of position NMOS tube connects the positive plate of the compensating electric capacity, source ground, grid connection by the clamper current-limiting resistance
The output end of the rest-set flip-flop.
By using above-mentioned technical proposal, the utility model has the advantages that：
Due to the magnitude of voltage of the switch of chip one compensating electric capacity of maximum conducting correspondence, to the clamp value of compensating electric capacity voltage not
The voltage can be less than, otherwise the ON time of chip does not just reach the maximum ON time of chip, if while to compensating electric capacity electricity
When the clamp value of pressure is too high, the time needed for loop response adjustment from compensating electric capacity clamping state to stable state is longer, therefore, this
Utility model enables module by setting up clamper, and it can enable compensating electric capacity clamper mould according to the maximum ON time signal of switch
Block carries out clamper to the voltage of compensating electric capacity, it is thus possible to which the adaptive voltage clamping by compensating electric capacity is in the maximum conducting of switch
Between corresponding compensating electric capacity voltage, so as on the premise of compensating electric capacity normal working voltage scope is not influenceed, reduce as far as possible
Time needed for loop response adjustment of the circuit from compensating electric capacity clamping state to stable state, it is to avoid output is in overshoot shape for a long time
State.
Brief description of the drawings
Fig. 1 is the circuit theory diagrams of existing compensating electric capacity clamp circuit；
Fig. 2 for the utility model embodiment a kind of improvement repeatedly quick power-on and power-off loop response compensating electric capacity clamper electricity
The circuit theory diagrams on road；
Fig. 3 is the waveform corresponding diagram of key node in the utility model.
Embodiment
Below in conjunction with the accompanying drawings, preferred embodiment of the present utility model is provided, and is described in detail, makes to be better understood when
Function of the present utility model, feature.
The compensating electric capacity clamp circuit of quick power-on and power-off loop response is used to drive LED repeatedly for improvement of the present utility model
The external compensating electric capacity of chip carries out clamper, as shown in Fig. 2 it includes compensating electric capacity charging module 1, compensating electric capacity clamper module
2 and clamper enable module 3.Wherein, compensating electric capacity charging module 1 includes transconductance modulator GM；Compensating electric capacity clamper module 2 includes pincers
Position NMOS tube M1 and clamper current-limiting resistance R0；Clamper, which enables module 3, includes comparator, current source I0, nor gate NOR, RS triggering
Device, compensating electric capacity Ccomp, slope electric capacity Cramp and slope electric capacity reset NMOS tube M2.
In the present embodiment, above-mentioned transconductance modulator GM positive input is connected to receive a benchmark with a reference voltage terminal
Voltage vref1, negative input is connected to receive a chip output current feedback signal Io_ with chip output current feedback end
Fb, output end is connected with compensating electric capacity Ccomp positive plate, with output voltage comp.
The positive input of above-mentioned comparator is connected to receive slope capacitance voltage with slope electric capacity Cramp positive plate
Vramp, negative input is connected with compensating electric capacity Ccomp positive plate to receive compensating electric capacity voltage comp, and its output end is defeated
Go out a cut-off signals ton.
Above-mentioned current source I0 input connection power vd D, output end is connected with slope electric capacity Cramp positive plate.
Above-mentioned nor gate NOR, its first input end is connected with the output end of comparator, and its second input and a switch are most
Big ON time signal end is connected, and to receive the maximum ON time signal tonmaxb of a switch, (the maximum ON time of switch is core
The basic parameter of piece, its value difference chip can difference), its output end is connected with the set end of rest-set flip-flop.
Above-mentioned rest-set flip-flop, its reset terminal is connected with a chip output switch Continuity signal end, to receive chip output
Switch-on signal swon, its set end AND OR NOT gate NOR output end are connected, its output end and clamper NMOS tube M1 grid
It is connected and enables signal clamp to export a clamper.
Above-mentioned slope electric capacity Cramp, its negative pole plate earthing, positive plate is connected with comparator positive input.
Above-mentioned clamper NMOS tube M1, its source ground, drain electrode is connected with clamper current-limiting resistance R0, grid and rest-set flip-flop
Output end is connected.
Above-mentioned clamper current-limiting resistance R0 one end is connected with clamper NMOS tube M1 drain electrode, the other end and compensating electric capacity
Ccomp positive plate is connected.
Above-mentioned slope electric capacity resets NMOS tube M2, and its drain electrode is connected with slope electric capacity Cramp positive plate, and negative plate connects
Ground, grid is connected with a chip output switch cut-off signals end, to receive a chip output switch cut-off signals swoff.
Operation principle of the present utility model is described in detail below：
As shown in Figures 2 and 3, during the conducting of LED drive chip output switch, swon is high level, and swoff is low electricity
Flat, M2 shut-offs, current source I0 is charged to slope electric capacity Cramp, and vramp is slowly risen by fixed slope.Compensated when vramp is reached
During electric capacity Ccomp voltage comp, the cut-off signals ton of comparator output is high level, enables LED drive chip output switch
Shut-off, then swon upsets are low level, and swoff upsets are high level, and M2 conductings, vramp is pulled down rapidly reset by M2 and waits LED
Driving chip output switch is reopened next time, now clamp signal clamp=0.If compensating electric capacity Ccomp voltage comp
Persistently rise too high, (the maximum switch conduction times in the maximum ON time cut-off of the switch of LED drive chip inner setting
Signal tonmaxb upsets are low level pulse, and during the shut-off of LED drive chip output switch), vramp is still unable to reach electricity
Comp is pressed, then ton continues low level, now nor gate NOR is output as height, and rest-set flip-flop set, clamp signal clamp=1 makes
M1 can be crossed drop-down clamper is carried out to compensating electric capacity Ccomp.Therefore clamp voltage final compensating electric capacity Ccomp is fixed on maximum and led
At comp voltages corresponding to the logical time.So as on the premise of compensating electric capacity normal working voltage scope is not influenceed, subtract as far as possible
Time needed for loop response adjustment of the small circuit from compensating electric capacity clamping state to stable state, it is to avoid output is overshooted in for a long time
State.
Above-described, preferred embodiment only of the present utility model is not limited to scope of the present utility model, this
Above-described embodiment of utility model can also make a variety of changes.I.e. every claims according to the present utility model application and
Simple, equivalent changes and modifications that description is made, fall within the claims of the utility model patent.This
The not detailed description of utility model is routine techniques content.
Claims (4)
1. a kind of improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response, for external to LED drive chip
Compensating electric capacity carry out clamper, it is characterised in that including a compensating electric capacity charging module, a compensating electric capacity clamper module and one pincers
Position enables module, and the clamper enables module and enables the compensating electric capacity clamper module according to the maximum ON time signal of a switch
Clamper is carried out to the voltage of the compensating electric capacity.
2. according to claim 1 improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response, its feature
It is, the clamper, which enables module, to be included：
One current source, its input connects a power supply；
One slope electric capacity, its positive plate connects the output end of the current source, negative pole plate earthing；
One slope electric capacity resets NMOS tube, and the positive plate of its connection slope electric capacity that drains, source ground, grid connects a core
Piece output switch cut-off signals end；
One comparator, its positive input connects the positive plate of the slope electric capacity, and negative input connects the compensating electric capacity
Positive plate；
One nor gate, its first input end connects the output end of the comparator, the maximum conducting of the switch of the second input connection one
Time signal end, to receive the maximum ON time signal of the switch；And
One rest-set flip-flop, its set end connects the output end of the nor gate, and reset terminal connects chip output switch conducting letter
Number end, output end connects the compensating electric capacity clamper module.
3. according to claim 1 improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response, its feature
It is, the compensating electric capacity charging module includes a transconductance modulator, its positive input terminal connects a reference voltage terminal, and negative input end connects
A chip output current feedback end is connect, output end connects the positive plate of the compensating electric capacity.
4. according to claim 2 improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response, its feature
It is, the compensating electric capacity clamper module includes a clamper NMOS tube and a clamper current-limiting resistance, the leakage of the clamper NMOS tube
Pole connects the positive plate of the compensating electric capacity by the clamper current-limiting resistance, and source ground, grid connects the rest-set flip-flop
Output end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621448922.XU CN206364698U (en) | 2016-12-27 | 2016-12-27 | It is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621448922.XU CN206364698U (en) | 2016-12-27 | 2016-12-27 | It is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206364698U true CN206364698U (en) | 2017-07-28 |
Family
ID=59376297
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621448922.XU Withdrawn - After Issue CN206364698U (en) | 2016-12-27 | 2016-12-27 | It is a kind of to improve repeatedly the compensating electric capacity clamp circuit of quick power-on and power-off loop response |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206364698U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106505845A (en) * | 2016-12-27 | 2017-03-15 | 上海灿瑞科技股份有限公司 | A kind of compensating electric capacity clamp circuit for improving repeatedly quick power-on and power-off loop response |
-
2016
- 2016-12-27 CN CN201621448922.XU patent/CN206364698U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106505845A (en) * | 2016-12-27 | 2017-03-15 | 上海灿瑞科技股份有限公司 | A kind of compensating electric capacity clamp circuit for improving repeatedly quick power-on and power-off loop response |
| CN106505845B (en) * | 2016-12-27 | 2018-10-02 | 上海灿瑞科技股份有限公司 | A kind of compensating electric capacity clamp circuit improving repeatedly quick power-on and power-off loop response |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20170728 Effective date of abandoning: 20181002 |