Temperature sensor of a CPU and PWM controller thereof

1. Technical Field

The present disclosure relates to power supply circuits, and particularly to a power supply circuit for providing power to a CPU (central processing unit).

2. Description of Related Art

With the rapid development of personal computers, development of high performance components for computers have brought about a corresponding increase in power use. A CPU has a crucial effect on the stability of the computer. A power supply circuit is specially designed for providing power to the CPU.

Referring to FIG. 1 , a typical power supply circuit for a CPU, according to the prior art, includes a PWM (pulse-width modulation) controller 90 which provides three pulse signals. The three pulse signals have different phases, such as phase 1 , phase 2 , and phase 3 . Each of the three pulse signals controls a corresponding switch on or off on different time to provide multiphase power source to the CPU. The multiphase power source usually generates less heat than single phase power source, so the CPU can run more stable. However, the pulse signals are easily interfered with and generate disorder jitters which cause the power provided to the CPU to be unstable and result in the CPU generating a an excess of heat.

Therefore, there is room for improvement within the art.

Many aspects of the embodiments can be better understood with references to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a block view of a conventional power supply circuit for a CPU, according to the prior art.

FIG. 2 is a block view of an embodiment of a power supply circuit for a CPU.

FIG. 3 is a circuit view of the power supply circuit of FIG. 2 .

The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.

Referring to FIG. 2 , a power supply circuit in an embodiment for providing power to a CPU 10 , includes a PWM controller 20 , a temperature feedback circuit 40 , and a temperature sensor 60 . The temperature feedback circuit 40 is connected to the PWM controller 20 . The temperature sensor 60 is connected to the temperature feedback circuit 40 . The temperature sensor 60 is capable of detecting a current temperature of the CPU 10 , and generating a current temperature signal that is sent to the temperature feedback circuit 40 .

Referring to FIG. 3 , the PWM controller 20 includes a plurality of pins, such as pin COMP, pin FB, pin IDROOP, pin VDIFF, pin PHSAE 1 , pin PHSAE 2 , pin PHSAE 3 , and so on. The pin COMP is used to trigger the PWM controller 20 to adjust the pulse signals outputted at the pins PHASE 1 , PHASE 2 , and PHASE 3 according to the current temperature of the CPU 10 .

The temperature feedback circuit 40 includes a first resistor R 1 , a second resistor R 2 , a third resistor R 3 , a fourth resistor R 4 , a fifth resistor R 5 , a sixth resistor R 6 , a first capacitor C 1 , a second capacitor C 2 , and a third capacitor C 3 .

The temperature sensor 60 can be a minus temperature coefficient thermal resistor T. The thermal resistor T is located adjacent the CPU 10 to measure the current temperature of the CPU 10 . The thermal resistor T includes a first end T 1 and a second end T 2 . The first end T 1 of the thermal resistor T is connected to a first end of the first resistor R 1 . A second end of the first resistor R 1 is connected to the pin COMP of the PWM controller 20 via a RC circuit. The RC circuit is composed of the second resistor R 2 and the first capacitor C 1 . The second capacitor C 2 is connected in parallel with the RC circuit and between the first resistor R 1 and the pin COMP. The second end of the first resistor R 1 is connected to the pin FB directly and further connected to the pin IDROOP via the third resistor R 3 . The second end of the first resistor R 1 is connected to the pin VDIFF via the third capacitor C 3 and the fourth resistor R 4 . The third capacitor C 3 and the fourth resistor R 4 are connected in series. The first end T 1 of the thermal resistor T is connected to the pin VDIFF via the fifth resistor R 5 . The second end T 2 of the thermal resistor T is connected to the pin VDIFF via the sixth resistor R 6 .

In operation, when the thermal resistor T detects that the temperature of the CPU rises, a resistor value of the thermal resistor T decreases. A voltage on the thermal resistor T decreases, and a voltage on the pin COMP rises. The PWM controller 20 then adjusts the pulse signals outputted by the pins PHASE 1 , PHASE 2 , and PHASE 3 to maintain the pulse signals stably.

It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.