CN111555597A

CN111555597A - Residual current discharge circuit of DDR chip power supply circuit

Info

Publication number: CN111555597A
Application number: CN202010242203.7A
Authority: CN
Inventors: 赵新华; 郭旭; 胡旻韬; 付聪; 蔡宏; 田学林; 孔令宏
Original assignee: Wuhu Hongjing Electronics Co Ltd
Current assignee: Wuhu Hongjing Electronics Co Ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2020-08-18

Abstract

The invention aims to provide a residual current discharge circuit of a DDR chip power supply circuit, wherein a switch circuit composed of Q12 discharges VCC5V, when the base is at a high level, Q12 is in saturated conduction, namely R347 (100R) is connected to the ground in series at the input end of U6, and the capacitor at the input end of U6 is rapidly discharged through R347, so that residual current can be reliably discharged, and the system can be reliably started. The circuit has low cost, good effect and popularization.

Description

Residual current discharge circuit of DDR chip power supply circuit

Technical Field

The invention relates to the field of DDR (double data rate) chip power supply circuits, in particular to a residual current discharge circuit of a DDR chip power supply circuit.

Background

In a circuit for supplying power to a DDR chip, because the input end and the output end of a DC-DC chip are both provided with larger filter capacitors, residual electric quantity still exists in a certain period of time after power failure, poor reset can be caused, and the DDR chip cannot be normally started.

As shown in fig. 2: the circuit is a power supply circuit of a DDR3 chip, the input voltage is 5V, and the output voltage is 1.5V. U6 functions as a voltage down converter. The problem that the residual electric quantity is discharged rapidly after power failure needs to be solved.

Disclosure of Invention

In order to solve the above problems, the invention provides a residual current leakage circuit of a DDR chip power supply circuit, wherein a switch circuit composed of Q12 is used for leaking VCC5V, when a base is at a high level, Q12 is in saturated conduction, which is equivalent to that R347 (100R) is connected in series to the ground at an input end of U6, and a capacitor at the input end of U6 is rapidly discharged through R347, thereby solving the problems in the background art.

The invention aims to provide a residual current discharge circuit of a DDR chip power supply circuit, which comprises a VCC5V power supply input end, wherein the VCC5V power supply input end is connected with R347 in series, the R347 is connected with Q12 in series, the Q12 is connected with R253 in series, and the R253 is connected to the PF3# of an MCU; q12 is also connected in series with R254 and C125, and R254 and C125 are both connected in parallel; the VCC5V power supply input end is connected in series with U6, and 5V voltage input by the VCC5V power supply input end is output to be 1.5V through the voltage reduction and conversion action of U6; q12, R254 and C125 are all connected to ground.

The further improvement lies in that: r347 is 100R/+/-5%, R253 is 10K/+/-5% and R254 is 47K/+/-5%.

The further improvement lies in that: when the base is high, the Q12 is saturated and turned on, which is equivalent to connecting R347 to ground in series at the input end of U6, the input end capacitor of U6 is rapidly discharged through R347.

The control end of the circuit is PF3# of the MCU, and the discharge action is started back under two conditions, wherein one condition is that residual charges need to be discharged completely at the moment of power-on, so that the DDR3 chip is reset completely, and the system can be started normally; another situation is that the entire core board VDD5V power supply system needs to cooperate with the draining of residual charge during reset, so that the reset is more complete.

The invention has the beneficial effects that: the switch circuit composed of Q12 of the invention discharges VCC5V, when the base is high level, Q12 is saturated and conducted, which is equivalent to that R347 (100R) is connected in series to the ground at the input end of U6, the capacitor at the input end of U6 is discharged rapidly through R347, the residual electricity can be discharged reliably, and the system can be started reliably. The circuit has low cost, good effect and popularization.

Drawings

Fig. 1 is a circuit diagram of the present invention.

Fig. 2 is a prior art circuit diagram in the background of the invention.

Fig. 3 is a diagram illustrating the residual charge draining effect of the present invention.

Detailed Description

For the purpose of enhancing understanding of the present invention, the present invention will be further described in detail with reference to the following examples, which are provided for illustration only and are not to be construed as limiting the scope of the present invention.

As shown in fig. 1-3, the present embodiment provides a residual current discharging circuit of a DDR chip power supply circuit, which includes a VCC5V power input terminal, a VCC5V power input terminal is connected in series with R347, R347 is connected in series with Q12, Q12 is connected in series with R253, and R253 is connected to PF3# of an MCU; q12 is also connected in series with R254 and C125, and R254 and C125 are both connected in parallel; the VCC5V power supply input end is connected in series with U6, and 5V voltage input by the VCC5V power supply input end is output to be 1.5V through the voltage reduction and conversion action of U6; q12, R254 and C125 are all connected to ground. R347 is 100R/+/-5%, R253 is 10K/+/-5% and R254 is 47K/+/-5%.

When the base is high, the Q12 is saturated and turned on, which is equivalent to connecting R347 to ground in series at the input end of U6, the input end capacitor of U6 is rapidly discharged through R347.

The switch circuit composed of Q12 discharges VCC5V, Q12 is saturated and conducted when the base is at high level, which is equivalent to that R347 (100R) is connected in series with the input end of U6 to the ground, and the capacitor at the input end of U6 is rapidly discharged through R347, so that the residual electricity can be reliably discharged, and the system can be reliably started. The circuit has low cost, good effect and popularization.

Claims

1. The utility model provides a residual current bleeder circuit of DDR chip supply circuit which characterized in that: the power supply comprises a VCC5V power supply input end, wherein the VCC5V power supply input end is connected with R347 in series, the R347 is connected with Q12 in series, the Q12 is connected with R253 in series, and the R253 is connected to the PF3# of the MCU; q12 is also connected in series with R254 and C125, and R254 and C125 are both connected in parallel; the VCC5V power supply input end is connected in series with U6, and 5V voltage input by the VCC5V power supply input end is output to be 1.5V through the voltage reduction and conversion action of U6; q12, R254 and C125 are all connected to ground.

2. The residual current discharging circuit of the DDR chip supply circuit of claim 1, wherein: r347 is 100R/+/-5%, R253 is 10K/+/-5% and R254 is 47K/+/-5%.

3. The residual current discharging circuit of the DDR chip supply circuit of claim 1, wherein: when the base is high, the Q12 is saturated and turned on, which is equivalent to connecting R347 to ground in series at the input end of U6, the input end capacitor of U6 is rapidly discharged through R347.