CN102751860A - Soft-starting circuit with soft-loading function - Google Patents
Soft-starting circuit with soft-loading function Download PDFInfo
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- CN102751860A CN102751860A CN2012102559463A CN201210255946A CN102751860A CN 102751860 A CN102751860 A CN 102751860A CN 2012102559463 A CN2012102559463 A CN 2012102559463A CN 201210255946 A CN201210255946 A CN 201210255946A CN 102751860 A CN102751860 A CN 102751860A
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Abstract
The invention discloses a soft-starting circuit with soft-loading function. The soft-starting circuit comprises a frequency measurement circuit, a time delay circuit, a duty ratio detection circuit, a counter circuit, a digital-to-analog conversion circuit and a comparator circuit, wherein the frequency measurement circuit is connected with the counter circuit through a lead; the time delay circuit is connected with the duty ratio detection circuit through the lead; the duty ratio detection circuit is connected with the counter circuit through the lead; the counter circuit is connected with the digital-to-analog conversion circuit through the lead; the digital-to-analog conversion circuit is connected with the comparator circuit through the lead; according to the comparison of the output signal of the digital-to-analog conversion circuit and the saw-tooth signal produced by a system, a duty ration pre-excitation signal is outputted by the comparator circuit, so that the conduction of a switching tube is controlled, thereby solving the problems in the existing automobile electronic regulator that the capacitance cannot be integrated onto a chip as a soft-starting capacitor is used in the soft-starting circuit, and the capacitance is larger, the circuit application area and the cost are increased, and the intelligent control demand and the soft-starting time demand cannot be met.
Description
Technical field
The invention belongs to the automotive control circuit technical field, relate in particular to
OnePlant the soft starting circuit that has soft value-added tax function.
Background technology
Soft starting circuit is meant that being applied to various power management IC suppresses the chip enable stage owing to power switch pipe damages power switch pipe and other devices and generation mechanical torque etc. with the bigger surge current of 100% duty ratio conducting generation; The effect of car electronic adjuster soft start function is: when load changes, reduce the variation of engine speed, duty ratio increases gradually when soft start works, and the belt of generator is within reason to be tightened.If adjuster does not have soft start, when chip the startup stage or load when increasing, the excitation duty ratio increases immediately; Exciting current is along with increase; The excitation torque increases makes the load of automobile engine increase, and belt is along with anxiety, and the rotating speed of engine is very responsive to the variation of load; Mechanical torque can take place and cause engine misses in the unexpected increase of this duty ratio, and soft start function will be avoided the generation of this adverse effect; At present; Known soft starting circuit is through the current source soft start voltage that charging obtains rising on the slope to electric capacity; With soft start voltage and sawtooth voltage relatively, obtain the control signal that a duty ratio increases gradually and come the conducting of control switch pipe, thereby reach the purpose of soft start.The advantage of this method is to be simple and easy to usefulness, and shortcoming is to need a soft start capacitor to control soft-start time, and this electric capacity is often bigger, and is difficult to flexible control, can't be integrated on the chip, and this will increase uses area and application cost.Especially the circuit of this work under low frequency of car electronic adjuster, should the startup stage realize that soft start realizes soft loading in normal work stage again, intelligent control is had relatively high expectations, soft-start time needs 3-5S, capacitive way can't be competent at.
Summary of the invention
The technical problem that the present invention will solve: provide
OnePlant the soft starting circuit that has soft value-added tax function; To solve in the present car electronic adjuster soft starting circuit because employing soft start capacitor and electric capacity volume are bigger; What cause can't be integrated on the chip; The circuit application area increases and cost increases, and can not satisfy problems such as intelligent demand for control and soft-start time demand.
Technical scheme of the present invention:
OnePlant the soft starting circuit that has soft value-added tax function, it comprises:
Frequency measurement circuit, the square wave incoming frequency that converts according to the generator phase voltage is confirmed the operating state of circuit, frequency measurement circuit is connected through lead with counter circuit;
Delay circuit, for duty detection circuit provides reset signal, delay circuit is connected through lead with duty detection circuit;
Duty detection circuit is used to detect the duty ratio in each excitation cycle, and duty detection circuit is connected through lead with counter circuit;
Counter circuit provides digital input signals to D/A converting circuit, is connected through lead with D/A converting circuit;
D/A converting circuit changes the counter circuit digital input signals into analog signals, and to produce soft start voltage, D/A converting circuit is connected through lead with comparator circuit;
Comparator circuit compares according to the output signal of D/A converting circuit and the sawtooth signal of system's generation, exports a conducting that duty ratio pre-excitation signal removes the control switch pipe.
Frequency measurement circuit comprises that two bands reset, keep d type flip flop and latch of function, and two d type flip flops constitute one two counter, the exit of the termination latch that resets of two digit counters.
Duty detection circuit comprises five digit counters and five latchs compositions that five d type flip flops constitute, and five d type flip flops are formed one five digit counter.
Counter circuit comprises five five digit counters with the d type flip flop formation that can put number, reset and keep function.
Beneficial effect of the present invention:
Circuit of the present invention adopts count the number of words analog conversion circuit control, frequency measurement circuit and duty detection circuit; The function of soft start has not only realized powering on; And when when the circuit operate as normal, causing voltage to descend on a large scale owing to the application of heavy load, this circuit can start soft value-added tax function, has avoided heavy load to use heavy current impact and the mechanical torque phenomenon that causes; Soft-start time is easy to control; Can be integrated in the low frequency system, be easy to realize pre-excitation, can either the startup stage realize soft start function; Again can be because the soft value-added tax function of Application and implementation of heavy load when operate as normal; Solved in the present car electronic adjuster soft starting circuit owing to adopting can't being integrated on the chip that soft start capacitor and capacity ratio cause greatly, the circuit application area increases and the cost increase, and can not satisfy problems such as intelligent demand for control and soft-start time demand.
Description of drawings:
Fig. 1 is an elementary diagram of the present invention.
Embodiment:
OnePlant the soft starting circuit that has soft value-added tax function, it comprises (see figure 1):
Frequency measurement circuit, the square wave incoming frequency that converts according to the generator phase voltage is confirmed the operating state of circuit, frequency measurement circuit is connected through lead with counter circuit; Frequency measurement circuit comprises that counter that one two bit strip resets and a latch form, and reference frequency pulse input end phase_test is the exit of latch and through receiving the reset terminal of two digit counters after the time-delay, and reference frequency pulse input end phase_test connects the narrow pulse signal that frequency is 1/2 times of incision speed-frequency; Phase place input phase connects pulse signal as count pulse; If can be 1/2 times of narrow pulse signal cycle inside counting of cutting speed-frequency more than or equal to 2, then the phase frequency reaches the incision rotating speed, latchs to be output as low level; Permission counter circuit counting; The beginning soft start operation withdraw from pre-excitation, otherwise counter circuit is in reset mode; Do not count, soft starting circuit is in the pre-excitation state.The pre-excitation duty ratio can be through setting overlapping resistance string value and the sawtooth waveforms of the first reference voltage terminal VH compare to confirm; The magnitude of voltage of D/A converting circuit output was not exactly the value of the first reference voltage terminal VH when counter circuit was not counted, and the value of the first constant reference voltage terminal VH and sawtooth waveforms relatively obtain the pre-excitation signal of a constant duty ratio.
Delay circuit; For duty detection circuit provides reset signal; Delay circuit is connected through lead with duty detection circuit, and the input of delay circuit is connected with the latch signal end latch of duty detection circuit, and output is connected with the internal counter reset terminal of duty detection circuit.
Duty detection circuit; Be used to detect the duty ratio in each excitation cycle; Duty detection circuit is connected through lead with counter circuit, and duty detection circuit comprises five digit counters and five latchs compositions that five d type flip flops constitute, and five d type flip flops are formed one five digit counter; Five outputs of duty detection circuit are connected with the several inputs of putting of counter circuit respectively; The output level of the latch signal end latch of duty detection circuit and the pwm control circuit of system disconnected provides latch signal and through delay circuit reset signal is provided, and the count pulse input cp1 of duty detection circuit is connected with system clock.
Counter circuit provides digital input signals to D/A converting circuit, is connected through lead with D/A converting circuit; Counter circuit has by five can put five digit counters that the d type flip flop of counting, reset, keep function constitutes; Rolling counters forward can maintain the original state when full and no longer count, and finish soft start this moment, overflows end C end output high level; The gating AND circuit; As soft loading waiting signal, five outputs of counter circuit, five inputs corresponding with D/A converting circuit connect, and count pulse input CP end is connected with the count pulse of control soft-start time; Counter circuit overflow end C and being connected with an input of door; With the soft loading end of another input termination of door, be connected with the number end PE that presets of counter with the output of door, put the number end and be connected with the corresponding output of duty detection circuit respectively for five of counter circuit.
D/A converting circuit changes the counter circuit digital input signals into analog signals, and to produce soft start voltage, D/A converting circuit is connected through lead with comparator circuit; D/A converting circuit is five a digital to analog converter; D/A converting circuit adopts overlapping resistor converter structure; The first reference voltage terminal VH and the second reference voltage terminal VL are the two ends of overlapping resistor, connect upper voltage limit and the lower voltage limit of reference voltage in order to the decision soft start voltage; The upper voltage limit of sawtooth waveforms of the present invention is 3.5V; Lower voltage limit is 2.5V; When D/A converting circuit is output as 3.2V and the comparator circuit comparison can obtain the pre-excitation duty ratio of 29% duty ratio; Therefore the first reference voltage terminal VH is connected with the 3.2V reference voltage source; Second reference voltage terminal VL end is connected with the 2.5V reference voltage source, and the input of the decoder circuit in the D/A converting circuit is connected with the output to low level of the high position of counter circuit respectively from a high position to the low level, and the output of D/A converting circuit is connected with the first input end of comparator circuit.
Comparator circuit; Compare according to the output signal of D/A converting circuit and the sawtooth signal of system's generation; The conducting that output out output duty cycle pre-excitation signal removes the control switch pipe, the sawtooth signal that system produces is received the second input Vramp of comparator circuit.
Operation principle of the present invention: when circuit powered on, automobile just started, and the phase voltage frequency of automobile current generator is lower; And the termination that resets of two digit counters in the frequency measurement circuit is that frequency is the burst pulse of 1/2 times of incision speed-frequency, the phase frequency pulse is counted in the cycle in each burst pulse, if rolling counters forward to 2 item is overflowed; No longer counting keeps original state, latches overflow status when the burst pulse one-period finishes; Then two digit counters are resetted, when overflowing, latch is output as low level; Otherwise be high level, the output of latch is the output of frequency measurement circuit.Therefore when latch is output as low level, phase frequency umber of pulse at 1/2 times of time counting of cutting frequency is described more than or equal to 2, promptly the phase frequency is more than or equal to one times incision frequency.
In order to let automobile start easily, when phase voltage is lower than one times of incision rotating speed, make adjuster be in a less fixed duty cycle conducting state; It is the pre-excitation state; Therefore this soft starting circuit has designed the pre-excitation function, because the output of frequency measurement circuit is connected with the reset terminal R of counter circuit, when frequency measurement circuit is output as high level; Its two digit counter is in reset mode, does not count.Obtain the voltage that amplitude is identical with reference voltage through D/A converting circuit conversion back; This voltage compares through comparator circuit and sawtooth voltage; The output of comparator circuit just can obtain the conducting that the definite pre-excitation signal of a duty ratio removes the control switch pipe, just can easily control the duty ratio of pre-excitation state through the value of setting reference voltage.Promptly confirm the size of pre-excitation duty ratio through the value of setting reference voltage according to system's needs.
After the phase frequency reaches one times incision rotating speed; The frequency measurement circuit output low level; Allow its two digit counter to begin counting; Change through D/A converting circuit, thereby obtain a ramp voltage, this voltage and comparator circuit compare and just can obtain a duty ratio and increased the soft start square-wave signal that reaches 100% duty ratio by pre-excitation state duty ratio gradually.When its two digit counter count down to when overflowing, spill over is controlled two digit counters and is stopped counting, keeps overflow status, and soft start finishes, and soft start this moment is output as the waveform of duty ratio 100%.And because the output of soft starting circuit and the output of pwm controller are the relations of logical AND, this moment, the control of system was transferred the pwm controller to.
The latch signal end latch termination of duty detection circuit be the inversion signal of the pwm signal of pwm controller output; Therefore when latch signal end latch end is low level; Duty detection circuit allows its five inner digit counters counting; When latch signal end latch end for high level the time, the latch of the rising edge of latch signal end latch end through inside gets off the state latch of five digit counters this moment, through delay circuit time-delay back five digit counters carried out zero clearing; Guarantee to latch afterwards earlier to reset, duty detection circuit is just noted the duty ratio of current pwm signal like this.Because also being D/A converting circuit, realizes by the sawtooth-wave circuit of this system; Soft start is also used D/A converting circuit; As long as the clock of D/A converting circuit is identical, waits for putting when soft load signal arrives and count to the counter circuit the inside through reducible its duty ratio of soft starting circuit.Duty detection circuit is writing down the duty ratio of last excitation period p wm controller output.
The counter circuit spill over connects and door, and this moment, soft load enable end LRC was ready, when heavy load is used; Only meet soft loading environment; Provide high level and hold to LRC, the state that at this moment just allows duty detection circuit to write down is put and is counted in the counter circuit, and counter circuit begins counting; The excitation duty ratio of the pwm controller output of this moment increased from the duty ratio in a last excitation cycle gradually; Avoided the application of heavy load to make voltage descend, the excitation duty ratio increases suddenly, realizes soft value-added tax function.
Claims (4)
1.
OnePlant the soft starting circuit that has soft value-added tax function, it comprises:
Frequency measurement circuit, the square wave incoming frequency that converts according to the generator phase voltage is confirmed the operating state of circuit, frequency measurement circuit is connected through lead with counter circuit;
Delay circuit, for duty detection circuit provides reset signal, delay circuit is connected through lead with duty detection circuit;
Duty detection circuit is used to detect the duty ratio in each excitation cycle, and duty detection circuit is connected through lead with counter circuit;
Counter circuit provides digital input signals to D/A converting circuit, is connected through lead with D/A converting circuit;
D/A converting circuit changes the counter circuit digital input signals into analog signals, and to produce soft start voltage, D/A converting circuit is connected through lead with comparator circuit;
Comparator circuit compares according to the output signal of D/A converting circuit and the sawtooth signal of system's generation, exports a conducting that duty ratio pre-excitation signal removes the control switch pipe.
2. a kind of soft starting circuit that has soft value-added tax function according to claim 1; It is characterized in that: frequency measurement circuit comprises that two bands reset, keep d type flip flop and latch of function; Two d type flip flops constitute one two counter, the exit of the termination latch that resets of two digit counters.
3. a kind of soft starting circuit that has soft value-added tax function according to claim 1 is characterized in that: duty detection circuit comprises five digit counters and five latchs compositions that five d type flip flops constitute, and five d type flip flops are formed one five digit counter.
4. a kind of soft starting circuit that has soft value-added tax function according to claim 1 is characterized in that: counter circuit comprises five five digit counters with the d type flip flop formation that can put number, reset and keep function.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012102559463A CN102751860A (en) | 2012-07-24 | 2012-07-24 | Soft-starting circuit with soft-loading function |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012102559463A CN102751860A (en) | 2012-07-24 | 2012-07-24 | Soft-starting circuit with soft-loading function |
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| CN102751860A true CN102751860A (en) | 2012-10-24 |
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| CN2012102559463A Pending CN102751860A (en) | 2012-07-24 | 2012-07-24 | Soft-starting circuit with soft-loading function |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106444459A (en) * | 2016-11-15 | 2017-02-22 | 贵州大学 | Control apparatus for detecting duty ratio of rectangular wave signal in real time and realization method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040113600A1 (en) * | 2002-11-14 | 2004-06-17 | Rohm Co., Ltd. | Switching power supply unit and controller IC thereof |
| US20090273324A1 (en) * | 2004-12-21 | 2009-11-05 | Rohm Co., Ltd. | Switching regulator |
| CN101741233A (en) * | 2009-11-16 | 2010-06-16 | 无锡芯朋微电子有限公司 | DC-DC switch power soft-start circuit of digital-to-analogue conversion control |
-
2012
- 2012-07-24 CN CN2012102559463A patent/CN102751860A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040113600A1 (en) * | 2002-11-14 | 2004-06-17 | Rohm Co., Ltd. | Switching power supply unit and controller IC thereof |
| US20090273324A1 (en) * | 2004-12-21 | 2009-11-05 | Rohm Co., Ltd. | Switching regulator |
| CN101741233A (en) * | 2009-11-16 | 2010-06-16 | 无锡芯朋微电子有限公司 | DC-DC switch power soft-start circuit of digital-to-analogue conversion control |
Non-Patent Citations (1)
| Title |
|---|
| 刘雨鑫等: "一种高集成度的DC-DC开关电源软启动电路", 《华中科技大学学报（自然科学版）》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106444459A (en) * | 2016-11-15 | 2017-02-22 | 贵州大学 | Control apparatus for detecting duty ratio of rectangular wave signal in real time and realization method thereof |
| CN106444459B (en) * | 2016-11-15 | 2023-04-28 | 贵州大学 | Control device for detecting duty ratio of rectangular wave signal in real time and implementation method |
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Application publication date: 20121024 |