Pulse width modulation control circuit reducing electromagnetic interference by frequency modulation of commercial power and method thereof
A pulse width modulation and control circuit technology, which is applied in the direction of conversion equipment, electrical components, and output power conversion devices with intermediate conversion to AC, can solve the problem of high frequency modulation signals, and achieve electromagnetic interference energy prevention. The effect of reducing the circuit and cost
Active Publication Date: 2012-10-03
UNISONIC TECH +1
View PDF2 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
However, due to the high frequency of the artificial FM signal produced inside the IC, the cycle of the FM signal can only be about 3.3ms. Putting the above formula (1) into it, it can be known that the actual effective working frequency points of the switching power supply are the most. about 110
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0038] see figure 1 As shown, the first preferred embodiment of the frequency modulation pulse width modulation control circuit 10 of the present invention is applied to an isolated switching power supply circuit, wherein the isolated switching power supply circuit includes:
[0039] A transformer TR1, including a primary side and a secondary side;
[0040] An active switch Q1, connected in series to the primary side power circuit of the transformer TR1;
[0041] A pulse width modulation circuit 10 includes a signal conversion unit 20 and a pulse width modulation controller 30, wherein please refer to figure 2 Shown:
[0042] The signal conversion unit 20 is connected to the mains power input terminal V AC , the mains signal is sampled and filtered, and a low-frequency first frequency modulation signal V is output FM . In this embodiment, a sampling unit 21 , a filter capacitor 22 , a voltage divider 23 and a high frequency filter capacitor 24 are included. The samplin...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention relates to a pulse width modulation control circuit reducing electromagnetic interference by frequency modulation of commercial power and a method thereof. The pulse width modulation control circuit comprises a signal conversion unit and a pulse width modulation controller, wherein the signal conversion unit samples and filters the commercial power signal to output the low-frequencyfrequency modulation signal, the pulse width modulation controller generates the synchronous pulse width modulation signal by the modulation according to the first frequency modulation signal and then outputs the frequency conversion switching signal according to the first frequency modulation signal, the switching current signal and the feedback signal; and thus, because the low-frequency commercial power signal is used as the frequency modulation signal to output the pulse width modulation signal determining the switching frequency of the switching signal, so the electromagnetic interference spectrum of a switching type power supply converter is widened, the energy of the electromagnetic interference is effectively dispersed, and the advantages of relatively simplifying the circuit and saving cost are achieved.
Description
technical field [0001] The invention relates to a pulse width modulation control circuit of a switching power supply circuit, in particular to a pulse width modulation control circuit and a method for reducing electromagnetic interference by frequency modulation of mains electricity. Background technique [0002] The so-called switching power converter uses switching power supply technology to convert an unregulated power supply into a regulated power supply that can be used by electrical appliances, so as to reduce the volume of the switching power converter. Although the switching power supply technology reduces the size of the switching power converter, it also affects the power supply and its peripheral equipment due to the electromagnetic interference generated by the active switching of the switching power converter. [0003] Therefore, devices for reducing electromagnetic interference, such as electromagnetic interference filters and transformer protection, need to be...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): H02M3/28H02M1/12H02M1/44
Inventor 高耿辉陈正和李铎王利
Owner UNISONIC TECH