CN215867837U

CN215867837U - Device for verifying normal work of RTC chip during switching of power supply

Info

Publication number: CN215867837U
Application number: CN202122292972.0U
Authority: CN
Inventors: 陈晨; 全成根; 朱梅
Original assignee: Taicang T&W Electronics Co Ltd
Current assignee: Taicang T&W Electronics Co Ltd
Priority date: 2021-09-22
Filing date: 2021-09-22
Publication date: 2022-02-18
Anticipated expiration: 2031-09-22

Abstract

The utility model discloses a device for verifying whether an RTC chip works normally when switching a power supply, which comprises a clock reading instrument and a test board, wherein the clock reading instrument is connected with the test board and is used for reading a real-time clock, the test board consists of a PCB (printed Circuit Board), a chip seat which is welded on the PCB and is used for placing the RTC chip, and a test circuit which is positioned on the PCB, the test circuit comprises a power circuit, a crystal oscillator circuit and an output measurement circuit, the power circuit is connected with a power pin of the chip seat and provides power for the RTC chip, the crystal oscillator circuit is connected with an oscillator input pin and an output pin of the chip seat, the output measurement circuit is connected with SDA (Serial bus architecture) and SCI (serial interface) pins of the chip seat, and the output end of the output measurement circuit is connected with the clock reading instrument. This novel circuit structure is simple, and it is easy to implement, and through the reliability of plug battery many times or disconnection external supply DC power supply verification RTC work, the device is purchased easily, and low cost has the price/performance ratio.

Description

Device for verifying normal work of RTC chip during switching of power supply

Technical Field

The utility model belongs to the technical field of electronic component testing, and particularly relates to a device for verifying whether an RTC chip works normally when switching a power supply.

Background

An RTC (Real time clock) chip is one of the most widely used consumer electronic products in daily life, and provides accurate Real time for people or provides an accurate time reference for an electronic system. In practical application and design, in order to guarantee that the RTC chip can normally work, the verification of external supply voltage and battery switching is required to be carried out, because button cell voltage size is different on the market, the voltage has the height to have, the quality is uneven, in order to ensure that the RTC chip function is normal, just need verify the RTC chip through inserting the button cell and removing the button cell, and read the clock information of RTC chip through I2C bus and judge whether the RTC chip work is normal, verify the reliability of RTC chip.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the utility model is to provide a device for verifying whether the RTC chip works normally when switching the power supply, so as to verify the reliability of the RTC chip.

In order to solve the problems, the technical scheme adopted by the utility model is as follows:

the utility model provides a whether device of normal work when verifying RTC chip switches power supply, reads the instrument and surveys the board including the clock, the clock reads the instrument and surveys the board and be connected for reading real-time clock, survey the board and comprises PCB board, the chip holder that is used for laying the RTC chip that welds on the PCB board and the test circuit that is located on the PCB board, the test circuit includes power supply circuit, crystal oscillator circuit and output measurement circuit, power supply circuit connects the power pin of chip holder, provides the power for the RTC chip, and crystal oscillator circuit connects the oscillator input and the output pin of chip holder, and output measurement circuit connects SDA, SCI pin of chip holder, and the output of output measurement circuit is connected the clock and is read the instrument.

Furthermore, the power circuit comprises an external direct current power supply, a battery, a diode, a current-limiting resistor and a filter capacitor, wherein the anode of the external direct current power supply is connected with the anode of the power supply of the chip holder through the diode, the cathode of the external direct current power supply is grounded and connected with the ground of the chip holder, the anode of the battery is connected with the anode of the power supply of the chip holder through the diode and the current-limiting resistor in sequence, the cathode of the battery is grounded, and the filter capacitor is connected between the anode of the power supply of the chip holder and the ground in parallel.

Furthermore, the power circuit further comprises a battery holder, wherein the positive electrode of the battery holder is connected with the positive electrode of the battery, and the negative electrode of the battery holder is connected with the negative electrode of the battery.

Furthermore, the crystal oscillator circuit comprises a crystal and a capacitor, wherein two ends of the crystal are respectively connected with an oscillator input pin and an oscillator output pin of the chip base, and two ends of the crystal are respectively grounded through the capacitor.

Furthermore, the output measurement circuit comprises a pull-up resistor, a protection resistor and an I2C interface, the protection resistor is connected in series between the SDA pin and the SCI pin of the chip holder and the I2C interface, the pull-up resistor is respectively connected between the SDA pin and the SCI pin of the chip holder and the positive power supply of the chip holder, and the I2C interface is externally connected with a clock reading instrument.

Preferably, the clock reading instrument is a PC upper computer.

Furthermore, the chip bases are provided with a plurality of power pins which are connected in parallel, the input pins of the oscillators are connected in parallel, the output pins of the oscillators are connected in parallel, the SDA pins are connected in parallel, and the SCI pins are connected in parallel.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

the circuit of the utility model has simple structure, easy implementation, easy purchase of devices, low cost and high cost performance, and can verify the working reliability of the RTC by plugging and unplugging the battery for many times or disconnecting the external supply direct current power supply.

Drawings

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

Detailed Description

The utility model is described in further detail below with reference to the attached drawings:

the utility model relates to a device for verifying whether an RTC chip normally works when switching a power supply. The verification mode is that the real-time clock of the chip is read by an external clock reading instrument for judgment, if the read clock is normal, the RTC chip is judged to be normal and reliable, otherwise, the RTC chip possibly has problems.

The test board is composed of a PCB, a chip seat welded on the PCB and used for placing an RTC chip, and a test circuit positioned on the PCB, wherein the test circuit comprises a power supply circuit 1, a crystal oscillator circuit 2 and an output measurement circuit 3, the power supply circuit is connected with a power supply pin VCC and a GND of the chip seat and used for providing power for the RTC chip, the crystal oscillator circuit is connected with an oscillator input OSCI and an output pin OSCO of the chip seat, the output measurement circuit is connected with a SDA and a SCI pin of the chip seat, and an output end of the output measurement circuit is connected with the clock reading instrument.

The power supply circuit comprises an external direct-current power supply, a battery BT, diodes D1, D2, a current-limiting resistor R4 and a filter capacitor C3, wherein the positive pole VCC of the external direct-current power supply is connected with the positive pole of a power supply of a chip holder through the diode D1, the negative pole of the external direct-current power supply is grounded and connected with the ground of the chip holder, the positive pole of the battery BT is connected with the positive pole of the power supply of the chip holder through the diode D2 and the current-limiting resistor R4 in sequence, the negative pole of the battery BT is grounded, and the filter capacitor C1 is connected between the positive pole of the power supply of the chip holder and the ground in parallel.

In order to facilitate the installation and the disassembly of the battery, the power circuit further comprises a battery seat, the positive electrode of the battery seat is connected with the positive electrode of the battery, and the negative electrode of the battery seat is connected with the negative electrode of the battery. The battery BT is connected with a diode D2 through the anode of the battery holder and is grounded through the cathode of the battery holder.

The crystal oscillator circuit comprises a crystal Y1 and capacitors C1 and C2, wherein two ends of the crystal Y1 are respectively connected with an oscillator input OSC1 and an output pin OSCO of the chip base, and two ends of the crystal are respectively grounded through the capacitors C1 and C2.

For the utility model, in order to test whether the RTC chip works normally, clock data of the RTC chip also needs to be read, so an output measurement circuit is also needed, the output measurement circuit comprises pull-up resistors R5, R6, protection resistors R2, R3 and an I2C interface J1, the protection resistors R3 and R2 are respectively connected in series between a chip holder SDA pin, an SCI pin and an I2C interface, the pull-up resistors are respectively connected between the chip holder SDA pin, the SCI pin and a positive power supply of the chip holder, and the I2C interface is externally connected with a clock reading instrument.

For the utility model, the clock reading instrument adopts a PC upper computer, and other devices such as a mobile phone, a singlechip and the like can be adopted.

For the utility model, because the RTC chip has various types and corresponds to different packaging structures, a plurality of chip holders are arranged to correspond to the RTC chips of various types, power supply pins of the plurality of chip holders are connected in parallel, input pins of the oscillator are connected in parallel, output pins of the oscillator are connected in parallel, SDA pins are connected in parallel, and SCI pins are connected in parallel. Therefore, when testing, only the RTC chip is put into the corresponding chip seat. Because the utility model tests the RTC chip, it is required to improve the test efficiency as much as possible, and the RTC chip is used in the actual production, therefore the chip holder adopts the clamping or buckling structure.

Example (b):

for the convenience of understanding, the following is a specific PCF85063AT, where VCC in this embodiment is used as an external dc power supply to supply power to the RTC chip, and the supply voltage is 3.3V. Currently, a chip PCF85063AT is used for verification, the PCF85063AT is an 8-pin chip, the selected RTC chip socket is 8 pins, and the pins correspond to the following: pin 1 is an OSCI signal input pin, a crystal Y1 provides a clock signal input, pin Y1 is a 32.768KHz frequency crystal, pin C2 is a load capacitor, a capacitance value 18pf, pin 2 is an OSCO signal output pin, a crystal Y1 provides a clock signal output, pin C1 is a load capacitor, a capacitance value 18pf, pin 3 is an INT pin, and is an interrupt control pin, the function of the embodiment is not used here, VCC is pulled up through a resistor R1, pin R1 is 1K, pin 4 is a chip ground pin, pin 5 is an SDA pin, a bus communication data pin I2C is connected to an interface J1I 2C through R3, 8 pins are connected through a resistor R5, pin R3 is 33 ohms and serves as a protection resistor, and pin R5 is a pull-up resistor 4.7K. Pin 6 is an SCI pin, pin I2C is a bus communication clock pin, and is connected to I2C interface J1 through R2, and is connected to pin 8 through resistor R6, and R2 is 33 ohms and serves as a protection resistor, and R6 is a 4.7K pull-up resistor. Pin 7 is the CLKOUT pin where the function is not used, pin 8 is the VCC chip supply pin, and C3 is the VCC to ground filter capacitor for voltage stabilization and power glitch elimination. Diodes D1 and D2 in the power circuit have a one-way conduction characteristic, R4 is a current-limiting resistor with the resistance value of 1K ohm, BT is a button battery with the voltage of about 3V, the anode of the diode is connected with the anode of the diode D2, the cathode of the diode is connected with the ground, and VCC of the diode D1 is connected with the anode of the diode. When the device is used, the RTC chip is placed on the RTC chip seat firstly, 3.3V voltage is input to the VCC, the button cell is inserted at the moment, the diode D1 and the D2 have the one-way conduction characteristic, the forward conduction voltage is 0.3V, the voltage of the button cell is generally about 3V, the VCC voltage of the external supply 3.3V is higher than that of the button cell, the VCC pin voltage of the RTC chip is provided by the external supply 3.3V at the moment, the clock information of the RTC chip is read through the I2C bus at the moment, the clock information can be read, the description is normal in work, the situation that whether the RTC chip can work normally can be obtained by repeatedly disconnecting the external supply 3.3V power supply or repeatedly plugging and unplugging different button cells for multiple times to verify.

Claims

1. The utility model provides a verify whether normal operating's device when RTC chip switches power supply which characterized in that: including the clock reading instrument and survey the board, the clock reads the instrument and is connected with surveying the board for read real-time clock, survey the board and comprises PCB board, the chip holder that is used for laying the RTC chip that welds on the PCB board and the test circuit that is located on the PCB board, test circuit includes power supply circuit, crystal oscillator circuit and output measuring circuit, the power pin of power supply circuit connection chip holder provides the power for the RTC chip, and crystal oscillator circuit connects the oscillator input and the output pin of chip holder, and SDA, the SCI pin of output measuring circuit connection chip holder, the output of output measuring circuit connect the clock and read the instrument.

2. The apparatus according to claim 1, wherein the apparatus for verifying whether the RTC chip is working normally when switching power supplies comprises: the power circuit comprises an external direct current power supply, a battery, a diode, a current-limiting resistor and a filter capacitor, wherein the anode of the external direct current power supply is connected with the power supply of the chip holder through the diode, the cathode of the external direct current power supply is grounded and connected with the ground of the chip holder, the anode of the battery is connected with the power supply of the chip holder through the diode and the current-limiting resistor in sequence, the cathode of the battery is grounded, and the filter capacitor is connected between the power supply of the chip holder and the ground in parallel.

3. The apparatus according to claim 2, wherein the apparatus for verifying whether the RTC chip is working normally when switching power supplies comprises: the power circuit further comprises a battery seat, the positive electrode of the battery seat is connected with the positive electrode of the battery, and the negative electrode of the battery seat is connected with the negative electrode of the battery.

4. The apparatus of claim 3, wherein the apparatus for verifying whether the RTC chip is working normally when switching power supplies comprises: the crystal oscillator circuit comprises a crystal and a capacitor, wherein two ends of the crystal are respectively connected with an oscillator input pin and an oscillator output pin of the chip base, and two ends of the crystal are respectively grounded through the capacitor.

5. The apparatus of claim 4, wherein the apparatus for verifying whether the RTC chip is working normally when switching power supplies comprises: the output measuring circuit comprises a pull-up resistor, a protection resistor and an I2C interface, wherein the protection resistor is connected in series between a chip holder SDA pin, an SCI pin and the I2C interface, the pull-up resistor is respectively connected between the chip holder SDA pin, the SCI pin and a positive power supply of a chip holder, and the I2C interface is externally connected with a clock reading instrument.

6. The apparatus according to any one of claims 1 to 5, wherein the apparatus for verifying whether the RTC chip is working normally when switching power supplies comprises: the clock reading instrument is a PC upper computer.

7. The apparatus of claim 6, wherein the apparatus for verifying whether the RTC chip is working normally when switching power supplies comprises: the chip bases are provided with a plurality of power pins which are connected in parallel, the oscillator input pins are connected in parallel, the oscillator output pins are connected in parallel, the SDA pins are connected in parallel, and the SCI pins are connected in parallel.