CN210724715U - Isolated square wave frequency reduction circuit - Google Patents
Isolated square wave frequency reduction circuit Download PDFInfo
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- CN210724715U CN210724715U CN201921902065.XU CN201921902065U CN210724715U CN 210724715 U CN210724715 U CN 210724715U CN 201921902065 U CN201921902065 U CN 201921902065U CN 210724715 U CN210724715 U CN 210724715U
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Abstract
The utility model discloses an isolated square wave frequency reduction circuit, which comprises a frequency reduction chip and an isolation chip, wherein the frequency reduction chip converts an input square wave signal into a low-frequency square wave signal with the frequency lower than the input square wave signal according to the number of counting pulses; the isolation chip is provided with an input end, an isolation output end and an isolation power supply end; the low-frequency square wave signal of the frequency reduction chip is connected to the input end of the isolation chip, an external isolation power supply is connected to the isolation power end of the isolation chip, the isolation chip uses the voltage value of the isolation power supply to isolate the amplitude of the low-frequency square wave signal, and the isolated low-frequency square wave signal is output through the isolation output end. The isolated square wave frequency reduction circuit of the utility model converts the input square wave signal into the low-frequency square wave signal, and solves the problem that the current low-speed measuring instrument can not measure the frequency of the high-speed square wave signal; meanwhile, the input signal and the output signal are completely isolated, the overshoot oscillation problem of the output signal of the frequency reduction chip is solved, the low-frequency square wave signal is smooth, and the quality of the low-frequency square wave signal is improved.
Description
Technical Field
The utility model relates to a power electronic technology field, concretely relates to isolated form square wave frequency reduction circuit.
Background
In the field of measurement, a plurality of sensors (physical quantity: torque, pressure, temperature and the like) or devices output square wave signals, the change of the physical quantity is reflected through the change of frequency, and a measuring instrument is used for measuring the square wave frequency and analyzing the actual physical quantity. At present, most measuring instruments have low sampling speed and cannot accurately measure high-frequency square wave signals, and therefore, a square wave frequency reduction circuit is required to reduce the frequency of the high-frequency square wave signals, for example, the actual square wave signals are 100Hz, 10Hz signals are obtained after frequency reduction, low-speed measuring equipment after frequency reduction conversion can also be used for measuring high-speed signals, and high-speed measuring instruments do not need to be purchased at high cost.
Disclosure of Invention
The utility model provides an isolated square wave frequency-reducing circuit, which converts a square wave signal into a low-frequency square wave signal and solves the problem that the current low-speed measuring instrument can not measure the frequency of the high-speed square wave signal; meanwhile, the input signal and the output signal are completely isolated, the stability of frequency reduction conversion of the square wave signal and the safety of circuit operation are effectively improved, the overshoot oscillation problem of the output signal of the frequency reduction chip is solved, the low-frequency square wave signal is smooth, and the quality of the low-frequency square wave signal is improved.
In order to solve the technical problem, the utility model provides an isolated square wave frequency reduction circuit, including frequency reduction chip and isolation chip, frequency reduction chip converts the input square wave signal into the low frequency square wave signal that the frequency is lower than this input square wave signal according to the number of count pulse; the isolation chip is provided with an input end, an isolation output end and an isolation power supply end; the output end of the frequency reduction chip is connected with the input end of the isolation chip, the low-frequency square wave signal of the frequency reduction chip is connected to the input end of the isolation chip, an external isolation power supply is connected to the isolation power supply end of the isolation chip, the isolation chip uses the voltage value of the isolation power supply to isolate the amplitude of the low-frequency square wave signal, and the isolated low-frequency square wave signal is output through the isolation output end.
The utility model discloses a preferred embodiment, further include keep apart the power and include two at least ways, the magnitude of voltage that two ways kept apart the power varies, two ways keep apart the power and connect through wire jumper or access switch respectively keep apart the power end.
In a preferred embodiment of the present invention, the isolation power supply further comprises 3.3V or 5V.
In a preferred embodiment of the present invention, the isolation chip further comprises a chip with one of the models ADUM1400, ADUM1401, and ADUM 1402.
The utility model discloses a preferred embodiment, further include that it still includes amplitude conditioning unit, square wave signal passes through output after amplitude conditioning unit decay amplitude, amplitude conditioning unit includes adjustable resistance one and adjustable resistance two, square wave signal inserts the regulation end of adjustable resistance one, the output series connection adjustable resistance two's of adjustable resistance one input, adjustable resistance two's output ground connection, back stage circuit is connected to adjustable resistance two's regulation end.
In a preferred embodiment of the present invention, the amplitude conditioning unit further outputs a square wave signal with an amplitude of 3.5V to 5V after attenuating the amplitude.
The utility model discloses a preferred embodiment, further include the back stage circuit includes CMOS driver chip, the square wave signal access that unit output is taked care of to the range CMOS driver chip, CMOS driver chip conversion square wave signal's amplitude is output after 3.3V, CMOS driver chip's output access frequency reduction chip's input.
The utility model has the advantages that:
the isolated square wave frequency reduction circuit of the utility model converts the input square wave signal into the low-frequency square wave signal, and solves the problem that the current low-speed measuring instrument can not measure the frequency of the high-speed square wave signal; meanwhile, the input signal and the output signal are completely isolated, the stability of frequency reduction conversion of the square wave signal and the safety of circuit operation are effectively improved, the overshoot oscillation problem of the output signal of the frequency reduction chip is solved, the low-frequency square wave signal is smooth, and the quality of the low-frequency square wave signal is improved.
Drawings
Fig. 1 is a structural diagram of an isolated square wave down converter circuit according to a preferred embodiment of the present invention;
FIG. 2 is a schematic circuit diagram of the isolation chip matching in the preferred embodiment of the present invention;
fig. 3 is a schematic circuit diagram of the matching between the sum amplitude conditioning unit and the CMOS driver chip in the preferred embodiment of the present invention.
Detailed Description
The present invention is further described with reference to the following drawings and specific embodiments so that those skilled in the art can better understand the present invention and can implement the present invention, but the embodiments are not to be construed as limiting the present invention.
Examples
The present embodiment discloses an isolated square wave down-conversion circuit, which includes a down-conversion chip U1 and an isolation chip U2, as shown in fig. 1 to 3. The frequency reduction chip U1 converts the input square wave signal into a low-frequency square wave signal with the frequency lower than that of the input square wave signal according to the number of the counting pulses; here, the down chip U1 has a counter integrated therein, and the down factor is determined according to the number of pulses counted by the counter. For example, one count pulse, down-doubled; two counting pulses, down four times. Corresponding to the input square wave signal of 100Hz, the frequency is respectively reduced to 50Hz and 25 Hz. In one implementation of this embodiment, the down-conversion chip U1 may be an EC4PE6E22C8N chip.
The isolation chip U2 has an input terminal VI, an isolation output terminal VO, an input power terminal VDD1 and an isolation power terminal VDD 2; the working voltage (usually 3.3V) of the isolation chip is accessed through an input power supply end VDD1, the output end of the down-conversion chip is connected with the input end VI of the isolation chip, the output low-frequency square wave signal is accessed to the input end of the isolation chip U2, the external isolation power supply is accessed to the isolation power supply end of the isolation chip, the isolation chip U2 isolates the amplitude of the low-frequency square wave signal by using the voltage value of the isolation power supply, and the isolated low-frequency square wave signal is output as VO through the isolation output end.
On the one hand, the isolation chip plays a role in adjusting the voltage amplitude of the low-frequency square wave signal output by the frequency reduction chip: the voltage amplitude of the signal output by the isolation chip only depends on the voltage value of the power supply connected to the isolation power supply end, for example, when the isolation power supply end is connected to 5V voltage, the isolation chip outputs a low-frequency square wave signal with the amplitude of 5V; when the isolation power supply is connected with 3.3V voltage, the isolation chip outputs a low-frequency square wave signal with the amplitude of 3.3V. Therefore, the amplitude of the low-frequency square wave signal output by the frequency reduction chip is adjusted. The design is favorable for matching the use requirements of the rear-stage equipment of the frequency reduction chip on low-frequency square wave signals with different amplitude requirements.
On the other hand, the effects of input and output isolation and low-frequency square wave signal smoothing are achieved, and the quality of the low-frequency square wave signal is improved: the input square wave signal connected with the frequency reduction chip is connected into an oscilloscope, and the waveform of the input square wave signal is obviously seen from the oscilloscope, and the problem of overshoot oscillation is caused. The input and the output are completely isolated, the amplitude of the low-frequency square wave signal output by the isolation chip completely depends on the power supply voltage accessed by the isolation power supply end, the problem that the back-end equipment is affected by oscillation in the output process of the frequency reduction chip is avoided, the low-frequency square wave signal output by the isolation chip is accessed into an oscilloscope, and the low-frequency square wave signal output after being isolated by the isolation chip is obviously smooth.
The isolation power supply comprises at least two paths, and the two paths of isolation power supplies are respectively connected with the isolation power supply ends through jumper wires or access switches. And accessing corresponding isolated power supplies according to different requirements. Common isolated power supplies are 3.3V and 5V.
In the technical solution of this embodiment, the isolated chip includes a chip with one of the models admm 1400, admm 1401, and admm 1402.
In order to be compatible with input square wave signals with various amplitudes (to adapt to various application occasions), for example, 24V, 5V and 3.3V, the square wave frequency-reducing circuit further comprises an amplitude conditioning unit, the square wave signals are output after amplitude attenuation through the amplitude conditioning unit, the square wave frequency-reducing circuit comprises a first adjustable resistor R1 and a second adjustable resistor R2, the square wave signals are connected to an adjusting end of the first adjustable resistor R1, an output end of the first adjustable resistor R1 is connected with an input end of the second adjustable resistor R2 in series, an output end of the second adjustable resistor R2 is grounded, and an adjusting end of the second adjustable resistor R2 is connected with a post-stage circuit. The signal amplitude is attenuated through the first adjustable resistor R1 and the second adjustable resistor R2, and the attenuated signal amplitude is controlled to be 3.5V-5V and then is sent to a post-stage circuit. The post-stage circuit comprises a CMOS driving chip U3, the square wave signal output by the amplitude conditioning unit is connected to the CMOS driving chip U3, the amplitude of the square wave signal converted by the CMOS driving chip U3 is 3.3V and then is output, and the output end of the CMOS driving chip U3 is connected to the input end of a frequency reduction chip U1. The CMOS driving chip U3 performs secondary amplitude adjustment on the 3.5V-5V square wave signals output by the amplitude conditioning unit, so that the level amplitude which can be accepted by the frequency reduction chip can be matched conveniently, namely the 3.5V-5V square wave signals are converted into 3.3V input square wave signals, and the frequency reduction chip is prevented from being damaged because square wave signals which do not pass through the primary amplitude modulation or the primary amplitude modulation failure enter the frequency reduction chip.
In the technical solution of this embodiment, the CMOS driver chip may be a 74HC245 driver chip.
The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutes or changes made by the technical personnel in the technical field on the basis of the utility model are all within the protection scope of the utility model. The protection scope of the present invention is subject to the claims.
Claims (7)
1. An isolated square wave frequency reducing circuit is characterized in that: the frequency reduction chip converts an input square wave signal into a low-frequency square wave signal with the frequency lower than that of the input square wave signal according to the number of counting pulses; the isolation chip is provided with an input end, an isolation output end and an isolation power supply end; the output end of the frequency reduction chip is connected with the input end of the isolation chip, the low-frequency square wave signal of the frequency reduction chip is connected to the input end of the isolation chip, an external isolation power supply is connected to the isolation power supply end of the isolation chip, the isolation chip uses the voltage value of the isolation power supply to isolate the amplitude of the low-frequency square wave signal, and the isolated low-frequency square wave signal is output through the isolation output end.
2. The isolated square wave down conversion circuit of claim 1, wherein: the isolation power supply comprises at least two paths, the voltage values of the two paths of isolation power supplies are different, and the two paths of isolation power supplies are respectively connected with the isolation power supply ends through jumper wires or access switches.
3. The isolated square wave down conversion circuit of claim 2, wherein: the isolated power supply comprises 3.3V or 5V.
4. The isolated square wave down conversion circuit of claim 1, wherein: the isolation chip comprises a chip with one of the models ADUM1400, ADUM1401 and ADUM 1402.
5. The isolated square wave down conversion circuit of claim 1, wherein: the square wave signal is output after passing through the amplitude attenuation unit, the amplitude conditioning unit comprises a first adjustable resistor and a second adjustable resistor, the square wave signal is connected to an adjusting end of the first adjustable resistor, an output end of the first adjustable resistor is connected with an input end of the second adjustable resistor in series, an output end of the second adjustable resistor is grounded, and the adjusting end of the second adjustable resistor is connected with a rear-stage circuit.
6. The isolated square wave down conversion circuit of claim 5, wherein: the amplitude conditioning unit attenuates the amplitude and then outputs a square wave signal with the amplitude of 3.5V-5V.
7. The isolated square wave down conversion circuit of claim 5, wherein: the rear-stage circuit comprises a CMOS driving chip, the square wave signal output by the amplitude conditioning unit is connected to the CMOS driving chip, the amplitude of the square wave signal converted by the CMOS driving chip is 3.3V and then is output, and the output end of the CMOS driving chip is connected to the input end of the frequency reduction chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921902065.XU CN210724715U (en) | 2019-11-06 | 2019-11-06 | Isolated square wave frequency reduction circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921902065.XU CN210724715U (en) | 2019-11-06 | 2019-11-06 | Isolated square wave frequency reduction circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210724715U true CN210724715U (en) | 2020-06-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921902065.XU Active CN210724715U (en) | 2019-11-06 | 2019-11-06 | Isolated square wave frequency reduction circuit |
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| CN (1) | CN210724715U (en) |
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2019
- 2019-11-06 CN CN201921902065.XU patent/CN210724715U/en active Active
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