CN102969023B - Electrifying circuit of eMMC (Embedded Multi Media Card) in electronic product - Google Patents

Abstract

One is the power-on circuit of eMMC in electronic products, including power control circuit and discharge circuit; the power control circuit includes resistor R1, resistor R2, resistor R5, triode Q3, PMOS tube Q1, and capacitor C344; the discharge circuit includes Resistor R3 and NMOS transistor Q2; one end of resistor R5 is connected to SYS_RESET, the other end is connected to the base of transistor Q3, the emitter of transistor Q3 is grounded, the collector of transistor Q3 is connected to resistor R2, and the other end of resistor R2 is respectively connected to resistor R1 , the gate of the PMOS transistor Q1, the capacitor C344, and the gate of the NMOS transistor Q2 in the discharge circuit. The invention enables the eMMC Flash to be reliably reset and powered on, and is quickly discharged after the system is powered off, thereby improving the stability of the system.

Description

A power-on circuit of eMMC in an electronic product

【Technical field】

The invention belongs to the circuit field of electronic products, and specifically refers to a power-on circuit of eMMC in electronic products.

【Background technique】

eMMC (Embedded MultiMediaCard) is an embedded memory standard specification established by the MMC Association. A distinct advantage of eMMC is the integration of a controller in the package that provides a standard interface and manages the flash memory, freeing manufacturers to focus on other parts of product development and reducing time-to-market.

Nand Flash memory is a kind of Flash memory, which uses a non-linear macro-cell mode inside, which provides a cheap and effective solution for the realization of solid-state large-capacity memory. Nand Flash memory has the advantages of large capacity and fast rewriting speed. It is suitable for the storage of large amounts of data, so it has been more and more widely used in the industry, including digital cameras, MP3 walkman memory cards, small and exquisite U disks, and tablets. computer etc. However, since different brands of Nand Flash chips include Samsung, Toshiba, Hynix, or Micron, etc., and the Nand Flash process technology is updated quickly, and new ones are introduced every year on average, so when using Redesign is required according to each company's product and technical characteristics. For consumer electronics that need to launch products quickly, this is undoubtedly a waste of time and delays the development cycle. Therefore, the concept of encapsulating all memory and control chips for managing Nand Flash on one MCP like eMMC has gradually become popular.

The eMMC of the old design does not have a special reset signal. The reset of the chip is realized by writing the Reset command to the software after power-on. When this technology needs to be restarted after programming the storage device, or when digital products are powered on and off quickly, there will be incomplete power-on or incomplete charge discharge, which will affect the normal use of electronic products. .

A dedicated reset signal has been added to the newly designed eMMC design. However, both old and new designs of eMMC are still in circulation on the market, which creates great difficulties for the material replacement of electronic products. There may be a problem that the first batch of products is normal, but the second batch of products is not normal.

In view of this, the inventor has made in-depth research on the defects of the prior art, and this case has been produced.

【Content of invention】

The technical problem to be solved by the present invention is to provide a power-on circuit for eMMC in electronic products, so that eMMC Flash can be reliably reset and powered on, and quickly discharged after the system is powered off, improving the stability of the system.

The present invention adopts the following technical solutions to solve the above-mentioned technical problems:

One is the power-on circuit of eMMC in electronic products, including two parts: power control circuit and discharge circuit;

The power supply control circuit includes resistor R1, resistor R2, resistor R5, transistor Q3, PMOS transistor Q1, and capacitor C344; one end of resistor R5 is connected to SYS_RESET, the other end is connected to the base of transistor Q3, the emitter of transistor Q3 is grounded, and the transistor The collector of Q3 is connected to the resistor R2, and the other end of the resistor R2 is respectively connected to the resistor R1, the gate of the PMOS transistor Q1, the capacitor C344, and the gate of the NMOS transistor Q2 in the discharge circuit; the drain of the PMOS transistor Q1 is respectively connected to the resistor R1, Capacitor C344, and VCC30; the source of the PMOS transistor Q1 is connected to the resistor R3 of the discharge circuit, and VCC_FLASH;

The discharge circuit includes a resistor R3 and an NMOS transistor Q2; one end of the resistor R3 is connected to VCC_FLASH, the other end is connected to the drain of the NMOS transistor Q2, and the source of the NMOS transistor Q2 is grounded;

Among them, the model of transistor Q3 is 3904, the model of PMOS tube Q1 is WPM2341, and the model of NMOS tube Q2 is WNM2016;

The model of capacitor C344 is C0603.

The models of the resistors R1, R2, R3 and R5 are all R0603.

The packaging size of the transistor Q3, the PMOS transistor Q1 and the NMOS transistor Q2 is SOT23.

The capacity of the capacitor C344 is 0.1uF.

The advantages of the present invention are: the present invention makes the power-on reset of the eMMC controllable, and allows the eMMC to discharge the internal charge in the case of fast power-on and power-off, so as to ensure its reliable power-on, improve the stability of the system, and solve the problem of Material replacement problems encountered in mass production.

【Description of drawings】

The present invention will be further described below with reference to the accompanying drawings and embodiments.

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

【Detailed ways】

As shown in Figure 1, one is the power-on circuit of eMMC in electronic products, including two parts: power control circuit and discharge circuit;

The power supply control circuit includes resistor R1 (resistance value 100K), resistor R2 (resistance value 10K), resistor R5 (resistance value 10K), transistor Q3, PMOS transistor Q1, capacitor C344 (capacity 0.1uF); one end of resistor R5 is connected to SYS_RESET, the other end is connected to the base of the transistor Q3, the emitter of the transistor Q3 is grounded, the collector of the transistor Q3 is connected to the resistor R2, and the other end of the resistor R2 is respectively connected to the resistor R1, the gate of the PMOS transistor Q1, the capacitor C344, and the discharge circuit The gate of the NMOS transistor Q2; the drain of the PMOS transistor Q1 is respectively connected to the resistor R1, the capacitor C344, and VCC30; the source of the PMOS transistor Q1 is connected to the resistor R3 of the discharge circuit and VCC_FLASH;

The discharge circuit includes a resistor R3 (resistance 33Ω) and an NMOS transistor Q2; one end of the resistor R3 is connected to VCC_FLASH, the other end is connected to the drain of the NMOS transistor Q2, and the source of the NMOS transistor Q2 is grounded;

Among them, the model of transistor Q3 is 3904, the model of PMOS tube Q1 is WPM2341, and the model of NMOS tube Q2 is WNM2016;

The model of capacitor C344 is C0603.

The models of the resistors R1, R2, R3 and R5 are all R0603.

The resistance value of the resistor R5 only needs to ensure the base current when the triode Q3 is fully turned on. Generally, a resistor of 4.7K-47K is commonly used; the resistance value of the resistor R3 can be within 100Ω, and the smaller the resistance value, the faster the discharge; the resistor R1 The resistance of R2 is variable, but it must be ensured that when the transistor Q3 is turned on, the voltage across the resistor R1 is greater than the turn-on threshold voltage of the PMOS transistor Q1, that is, Vgs>2.5V. And because the larger the Vgs, the smaller the on-resistance of the NMOS transistor Q2, the smaller the loss, and considering the power consumption, the resistor R1 can be selected from 10K-100K, and the resistor R2 can be selected from 1K-10K.

The packaging size of the transistor Q3, the PMOS transistor Q1 and the NMOS transistor Q2 is SOT23.

The power supply control circuit is controlled by the PMOS transistor Q1 to turn on the power supply circuit, the control signal is generated by the resistor R5 and the transistor Q3, and the Vgs level that controls the conduction of the PMOS transistor Q1 is set by the resistor R1 and R2 voltage divider circuit.

The NMOS transistor Q2 of the discharge circuit controls the conduction of the charge discharge circuit, and the resistor R3 is used as a load resistance of the discharge circuit.

Before the system is powered on, the SYS_RESET pin is at a low level, and the transistor Q3 is cut off. At this time, the gate of the PMOS transistor Q1 is at a high level because of the pull-up of the resistor R1, and the Vgs of the PMOS transistor Q1=0v, so the PMOS transistor Q1 As a result, the eMMC is not powered on. And because the gate of the NMOS transistor Q2 is at a high level at this time, and Vgs=3V, the NMOS transistor Q2 is turned on, and a discharge circuit is formed through the resistor R1 to discharge the internal charge of the eMMC.

When the circuit is powered on and starts to work stably, SYS_RESET outputs a high level, controls the transistor Q3 to turn on, resistors R1 and R2 form a voltage divider, and the Vgs of the PMOS transistor Q1=-3V, so the PMOS transistor Q1 is turned on, VCC_FLASH=VCC30, The gate of the NMOS transistor Q2 is at a low level, Vgs=0.3V, the NMOS transistor Q2 is turned off, and the eMMC starts to be powered on.

After adopting the solution of the present invention, eMMC Flash can be reliably reset and powered on, and can be quickly discharged after the system is powered off, which improves the stability of the system and solves the problem of material replacement encountered in mass production.

The above descriptions are only preferred implementation examples of the present invention, and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. are the electrification circuits of eMMC in electronic product, it is characterized in that: comprise power control circuit and discharge circuit two parts;

Wherein power control circuit comprises resistance R1, resistance R2, resistance R5, triode Q3, PMOS Q1, electric capacity C344; Wherein resistance R5 one end is connected to SYS_RESET, the other end is connected to the base stage of triode Q3, the grounded emitter of triode Q3, the grid level of the NMOS tube Q2 in the other end difference contact resistance R1 of the collector contact resistance R2 of triode Q3, resistance R2, the grid of PMOS Q1, electric capacity C344, discharge circuit; Drain electrode contact resistance R1, electric capacity C344 and VCC30 respectively of PMOS Q1; The source electrode of PMOS Q1 connects resistance R3 and VCC_FLASH of discharge circuit;

Wherein discharge circuit comprises resistance R3 and NMOS tube Q2; Resistance R3 one end connects VCC_FLASH, and the other end connects the drain electrode of NMOS tube Q2, the source ground of NMOS tube Q2;

Wherein the model of triode Q3 model to be 3904, PMOS Q1 models be WPM2341, NMOS tube Q2 is WNM2016;

Wherein electric capacity C344 model is C0603.

2. a kind of is as claimed in claim 1 the electrification circuit of eMMC in electronic product, it is characterized in that: the model of described resistance R1, R2, R3, R5 is R0603.

3. a kind of is as claimed in claim 1 the electrification circuit of eMMC in electronic product, it is characterized in that: the package dimension of described triode Q3, PMOS Q1, NMOS tube Q2 is SOT23.

4. a kind of is as claimed in claim 1 the electrification circuit of eMMC in electronic product, it is characterized in that: described electric capacity C344 capacity is 0.1uF.