Patent Application
20090322301
1. Field of the Invention
The present invention relates to a technology for improving the efficiency of a power supply device, and more particularly to a control circuit and a control method of a power supply device for reducing the basic loss at a lower output load as well as improving the efficiency of a lower output load to achieve a power saving effect.
2. Description of the Related Art
As computers or other electronic devices generally come with a power supply device for converting a 110V or 220V AC utility power into a 3.3V, 5V or 12V DC power required by a hardware device such as a motherboard, a hard disk or an optical disk, the power supply device 90 as shown in
As the energy shortage issue becomes increasingly serious and a large number of personal computers are used in these days (according to the statistics provided by the Forrester Research, the total number of personal computers used as of the end of 2008 is up to one billion, the whole world can save tens of billions of kWh power per year if we can improve the operating efficiency of the power supply devices. Therefore, finding a way of enhancing the operating efficiency of a power supply device demands immediate attentions, breakthroughs, and feasible solutions.
In view of the shortcomings of the conventional power supply device with a poor operating efficiency at a lower output load and a poor structural design, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally developed a more efficient and power-saving control circuit for improving the efficiency of a lower load of a power supply device and a control method to overcome the aforementioned shortcomings and promote the development of the industry.
The primary objective of the present invention is to overcome the shortcomings of the prior art by providing a control circuit and a control method for improving the efficiency of a lower load of a power supply device, wherein the control circuit is added to two power stages, such that if a total output load is smaller than a predetermined load, then the control circuit will issue a control signal to turn off one of the power stage, and if the total output load is greater than the predetermined load, the closed power stage will be turned on again. With the control circuit, the invention can reduce the basic loss of the power stage at a lower output load to achieve a power saving effect and improve the economic efficiency.
The control circuit of the invention is applied to a power supply device of a switching or interleaved converter to achieve the foregoing objectives and effects, and the power supply device comprises two power stages, a pulse width modulator installed on the power stages, and an input power supply, such that after a power is inputted to the power supply device, an output power is integrated and outputted to drive a load; a control circuit, electrically coupled to the power supply device, for detecting a driving load of the power supply device and issuing a control signal for turning on or off one of the power stages.
The technical measures of the invention includes: an input stage, for inputting an AC power; two power stages, coupled to the input stage, and including a first power stage, a second power stage, a first control switch, a second control switch and a pulse width modulation (PWM), and the first power stage and the second power stage are coupled to the input stage and the first control switch respectively, and the second control switch is coupled to the first power stage and the second power stage respectively, and the pulse width modulation (PWM) is coupled to the first control switch and the second control switch; a control circuit, coupled to the first control switch and the second control switch, wherein the control circuit is coupled to the first power stage and the second power stage for detecting an output load of the first/second power stage.
The control method of the invention comprises the steps of:
(1) using a control circuit to set a predetermined output load value; (2) using the control circuit to detect a total output load of power stages; (3) comparing the total output load with the predetermined output load value; and (4) using the control circuit to turn on or off one of the power stages according to a comparison result.
To make it easier for our examiner to understand the objects, shape, characteristics and performance of the present invention, we used preferred embodiments accompanied with related drawings for the detailed description of the invention as follows.
Attachment shows an efficiency comparison table of two power stages when one of the power stages is turned off.
Referring to
The control circuit 20 is electrically coupled to the power supply device 10 for detecting a total output load of the power supply device 10. If the total output load of the power supply device 10 is smaller than a predetermined load, then a control signal will be issued to turn off one of the power stages 11, 12. If the total output load of the power supply device 10 is greater than the predetermined load, then the closed power stage 11, 12 will be turned on again, and the detection functions and the ON and OFF operations are maintained all the time to achieve the power-saving control effect.
Referring to
The control circuit 20 further comprises an output detection circuit and a magnetic hysteresis control circuit, and the control circuit 20 is coupled to the first control switch 113 and the second control switch 124, and the first power stage 111 and the second power stage 122 feed back an output load to the control circuit 20, so that the output detection circuit detects the output load of the first power stage 111 and the second power stage 122. If the total load is smaller than a predetermined load, then the control circuit 20 will issue a control signal to turn off one of the power stages 11, 12. If the output load is greater than the predetermined load, then the closed power stage 11, 12 will be turned on again. For instance, if the total load is set to 0˜40% of the output load, one of the power stages 11, 12 will be turned off. If the total load exceeds 40%, then the closed power stage 11, 12 will be turned on again. If the total load drops below 35% again, then one of the power stages 11, 12 will be turned off again. Such arrangement of using the control circuit 20 to maintain the detection of the output load and the operation of turning off/off the power stages 11, 12, so as to achieve the effects of reducing the basic loss of the two power stages at a low load and controlling the power saving effect all the time. Since one of the power stages is turned off at a low load, the power saving efficiency can be improved by 2.2% (as shown in the attachment), and thus the overall power saving effect is very significant for the huge number of personal computers, which constitutes a substantial contribution to the environmental protection of the earth and the utility of energies.
Referring to
The main feature of the present invention is the installation of the control circuit provided for detecting and turning ON/OFF the power stages to achieve the overall power saving effect. Similarly, the same principle in accordance with the aforementioned embodiments can be applied for detecting and controlling the ON/OFF of a plurality of power stages, and the pulse width modulation (PWM) can be implemented by a power factor correction (PFC) to achieve the equivalent power saving effect.
In summation of the above description, the present invention herein enhances the performance of the conventional structures and further complies with the requirements of patent application and is thus duly filed for the patent application.
While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.
