Analyze DDR2 memory power circuit

The current required for DDR2 and DDR3 memory is large, so most motherboards use switching power step-down mode (PWM).

Memory-powered switching power circuits are generally composed of pulse modulators (PWM), MOS transistors, inductors, and electrical memory, as shown in figure 1.

 

       Figure 1 physical diagram of the on-off power supply powered by memory.

The PWM circuit works as shown in figure 2. The PWM chip adjusts the output voltage by controlling the high-speed on and off of the upper and lower tubes. When the upper tube is turned on, the VIN charges the energy storage circuit of the inductor and capacitor through the upper tube and supplies power to the later stage. When the capacitor and inductor is full of electricity, the PWM chip controls and closes the upper tube, and opens the lower tube so that the energy storage circuit composed of inductor and capacitor can form a closed loop, so that the inductor and capacitor discharge continue to supply power to the later stage (the lower tube constitutes the discharge loop). In fig. 2, T1 is on and T2 is off. It can be seen from the diagram that the output voltage can be effectively controlled by controlling the duty cycle of T1.

Fig.2 The PWM circuit works.

Intel H61 single-bridge chip board works.

     The Intel H61 chipset is an upgrade of the H55 chipset, supporting the 1155-pin second-generation CPU. of 13, 15, and 17 The function of H61 chipset motherboard is greatly improved, and the ERP energy-saving circuit is set on the standby circuit of the motherboard, which greatly reduces the power consumption of the motherboard when it is on standby. The main difference between the H6I chipset and the normal motherboard after using the ERP energy-saving circuit is that there is no standby power supply before the motherboard does not press the switch. The Intel H6I chipset motherboard boot circuit works as shown in figure 1.

      Figure 1 operating principle block diagram of the motherboard boot circuit of the Intel H61 chipset.

The Intel H61 chipset motherboard boot circuit works as follows.

The first stage: the main board installed the battery BATI through R299 sent to the DI0 Schottky transistor positive pole, from the negative output RTCVCC for the bridge real-time clock circuit power, RTCVCC after R411 and C465 capacitor delay to get RTCRST# high-level reset South Bridge chip RTC circuit.

The second stage: plug in ATX power supply and connect 220V AC market power, ATX power output ATX_5VSB, through voltage regulator step down to SB_3VSB power supply to IT8728F, used for IT8728F chip trigger module and ERP module power supply.

The third stage: the short switch generates the PANSHW# trigger signal to the 75 pins of the IT8728F, outputs the SLP_SUS_L signal after the internal logic circuit conversion, controls the ERP energy-saving circuit to step down to get the standby power supply of the 3VSB to the bridge and the IT8728F. IT8728F gets standby power supply after internal delay from 85-pin output RSMRST# high-level signal to the bridge, notifying the main board of the bridge standby power supply is normal.          At the same time, the RSMRST# signal is pulled to the high level of the DPWROK through the resistor, and the transmission to the bridge indicates that the power supply is normal. The IT8728F internal delay then sends out the PWRON# of the 3.3V-0V-3.3V jump from the 72 feet to the bridge request to power on. The bridge sends a 3.3V continuous high-level SLP_S3# to the 71 pins of the IT8728F when standby conditions are normal and itself is normal, indicating that power is allowed. Finally, 1T8728F sends out a continuous low-level PSON# signal from 76 pins to pull down the green line of ATX power supply, so that the output of ATX power supply is + 12V, + 5V, + 3.3V to complete the power-up.

       This article is from Allicdata Electronics Limited.

What is the working principle of the sensor sensing electronics?

With the development of electronic technology, the electronic welcome device that uses pure electronic technology to realize the welcome function in many shopping malls or some brand stores is now produced.

Circuit working principle

When a person walks through the welcoming device, a shadow is generated, and the resistance of the photoresistor changes by the principle of the light resistance of the photoresistor. The sensor is produced by receiving the photoresistor signal. The schematic diagram of the inductive electronic welcome device circuit is shown below.

 

Inductive electronic welcome circuit schematic

Note: AC 220V power supply is used in the actual production process. Please design the specific power conversion circuit.

The inductive electronic welcome device is powered by a battery, and the system enters a wait state after power-on. Since the light is not blocked and directly irradiated on the photoresistor RG1, RG1 exhibits a resistance value. When the human body blocks a part of the light that is irradiated to the photoresistor, the intensity of the light received by the photoresistor changes, and the resistance value of RG1 changes. The current flowing through RG1 is coupled through the electrolytic capacitor C2, and amplified by the high gain of the transistor Q1 and the like, and then input to the inverting input terminal of the integrated circuit IC1. This signal and the output number input to the non-inverting input terminal are operated and amplified in the integrated circuit IC1.

After processing, a control signal is formed to drive the audio generating circuit inside the integrated circuit IC1 to work, resulting in "Hello, welcome“ audio signal, through SP1 to complete the electro-acoustic conversion, so that the human ear can hear this greeting.

This article is from Allicdata Electronics Limited. Reprinted need to indicate the source.