CN2736822Y

CN2736822Y - Clock module with temperature sensor

Info

Publication number: CN2736822Y
Application number: CN 200420076080
Authority: CN
Inventors: 李中泽; 黄少鹤
Original assignee: SHENGFAN ELECTRONICS CO Ltd WUHAN
Current assignee: SHENGFAN ELECTRONICS CO Ltd WUHAN
Priority date: 2004-07-23
Filing date: 2004-07-23
Publication date: 2005-10-26
Anticipated expiration: 2014-07-23

Abstract

The utility model discloses a clock module with temperature sensor. An element circuit is composed of a real-time clock chip, a crystal, a matching capacitance, a clock accuracy control capacitance, a peripheral device diode, and a resistor; a clock-frequency output unit circuit is composed of a clock output optical coupler, a resistor, and a transistor. The utility model is characterized in that a temperature sensor circuit is composed of a thermistor and a precision resister; all the devices are welded on a PCB board to form a packaging module; an external interface can be guided to a single-row curved needle with eight cores. Because of the utility model adopting the thermistor with low cost as the temperature sensor circuit, the utility model has advantages that the accurate timing is namely clock accuracy (daily error) <=0.5S(23 DEG C)<=1S(-20 DEG C-60 DEG C); 2. the cost of the thermistor is greatly lower than cost of the integrated temperature sensing chip, so that the utility model is low in cost; 3. the utility model adopts the single-row eight cores and the external connection is convenient in use.

Description

The clock module of band temperature sensor

Technical field

The utility model belongs to a kind of real-time clock product, is a kind of clock module with temperature sensor specifically.

Background technology

Use in the market that real-time clock is a lot of cheaply, it is to be made of clock module and peripheral circuit, owing to do not have compensating element, in the clock module, makes that the precision of this clock is not high.

Summary of the invention

The purpose of this utility model provides a kind of with the clock module of thermistor as the band temperature sensor of temperature sensor, to overcome above-mentioned deficiency.

To achieve these goals, the utility model is by real-time timepiece chip IC, 32768Hz crystal XT, matching capacitance C4, clock accuracy is adjusted capacitor C 1, C2, C3 and peripheral components diode D1, D2, capacitor C5, resistor R 1, R2 forms the clock unit circuit, clock output optocoupler GL, resistor R 3, R4, R5 and triode BG form clock frequency output unit circuit, be characterized in: also have a thermistor RT, precision resister R6 forms temperature sensor circuit, above-mentioned all devices all are welded on formation package module in back on the pcb board, and external interface causes on the single looper of 8 cores;

In the above-mentioned temperature sensor circuit of forming by thermistor RT, precision resister R6, thermistor RT1 connects with precision resister R6, its series connection end is connected with the single looper of 8 cores as the output ADT of temperature sensor circuit, the two ends of series circuit respectively with module in the anodal VDD of working power be connected with negative pole VSS.

Thermistor makes the utlity model has as temperature sensor circuit because the utility model adopts cheaply: 1, clock accurately: clock accuracy (day error) :≤0.5S (23 ℃)≤1S (20 ℃---60 ℃); 2, cost is very low: the thermistor cost is far below integrated temperature sensing chip; 3, adopt single 8 cores to be connected advantages such as easy to use with the outside.

Description of drawings

Fig. 1 is the utility model circuit theory diagrams.

Fig. 2 is the utility model profile and external cabling synoptic diagram.

Embodiment

Further specify the utility model below in conjunction with accompanying drawing.

The utility model can utilize the microprocessor of outer tape splicing A/D (mould/number) conversion to detect the voltage of thermistor, and magnitude of voltage is corresponding with the environment temperature of real-time clock module IC; Find out the time adjusted value under the Current Temperatures again by tabling look-up, time adjusted value accumulative total writes real-time clock module IC after a certain amount of.

The utility model external cabling sees Table 1:

Table 1

Symbol	Number of pins	Describe
Symbol	Number of pins	Describe	VDD	?1	External power source positive pole (3.3V-6.0V)
VSS	?2、5、7	The negative pole of external power source and battery	VDD	?1	External power source positive pole (3.3V-6.0V)
VSS	?2、5、7	The negative pole of external power source and battery	BATT	?3	External cell positive pole (3.0V or 3.6V)
ADT	?4	The temperature sampling output voltage signal	BATT	?3	External cell positive pole (3.0V or 3.6V)
ADT	?4	The temperature sampling output voltage signal	SCL_CL	?6	The serial clock input of clock chip
I/O_CL	?8	The serial data line of clock chip	SCL_CL	?6	The serial clock input of clock chip

Principle of work of the present utility model is:

Power unit: BATT connects external cell, VDD connects external power source, give clock chip IC power supply by diode D1, D2, capacitor C5, the voltage of external power source should be than the voltage of external cell about high 0.3V during operate as normal, to guarantee by external power source, when external power source cuts off the power supply, then power and guarantee that clock data do not make mistakes by external cell.

The serial clock input of the universal serial bus part of clock chip IC: SCL_CL end and clock chip IC links to each other, and the I/O_CL end links to each other with the serial data line of clock chip IC; Resistor R 1, R2 are the pull-up resistors on the universal serial bus of clock chip IC.Just can the parameter of clock chip IC be provided with behind the outside connection microprocessor.

Clock frequency output unit circuit: clock output optocoupler GL, resistor R 3, R4, R5 and triode BG form clock frequency output unit circuit.When the CLK_TEST end was high level, triode BG ended, and the light emitting diode of optocoupler GL ends; When the CLK_TEST end is low level, triode BG conducting, the light emitting diode conducting of optocoupler GL.Promptly know the accuracy of clock frequency by the frequency of measuring optocoupler GL output terminal.

The adjustment circuit of vibration of 23 ℃ of real-time clocks and precision: the oscillatory circuit of the oscillator composition 32768Hz that 32768Hz crystal XT, real-time timepiece chip IC are built-in; Matching capacitance C4, clock accuracy are adjusted the adjustment circuit of capacitor C 1, C2, C3 composition precision.Because the individual difference of 32768Hz crystal XT, real-time timepiece chip IC causes actual oscillation frequency may depart from 32768Hz, and real-time timepiece chip IC timing is based on this oscillation frequency, i.e. deviation may appear in timing.The output frequency that uses 8 demonstrations, precision to measure optocoupler GL as the frequency meter of 1ppm detects the precision of 23 ℃ of real-time clocks, by adjust capacitor C 1, (electric capacity increases, and frequency reduces for C2, C3; Electric capacity reduces, and frequency raises) guarantee clock accuracy [(day error) :≤0.5S (23 ℃)].

Temperature sensor circuit: thermistor RT1, precision resister R6 form temperature sensor circuit.23 ℃ of days of clock module, the error adjusted was for being not more than 0.5S.Because oscillation frequency can change with variation of temperature, i.e. the accuracy meeting of clock changes with variation of temperature, for the accuracy that guarantees clock need add temperature compensation.The resistance of thermistor RT can change with variation of temperature, and the voltage on the 4th pin of promptly single looper J102 can change with variation of temperature.As long as this clock module just is connected with the microprocessor of outside band A/D conversion can measures voltage, the environment temperature of magnitude of voltage and real-time clock module is corresponding; Find out the time adjusted value under the Current Temperatures again by tabling look-up, time adjusted value accumulative total to a certain amount of back writes the temperature compensation that real-time clock module can be realized clock easily by microprocessor.

The content that is not described in detail in this instructions belongs to this area professional and technical personnel's known prior art.

Claims

1, a kind of clock module with temperature sensor, by real-time timepiece chip (IC), 32768Hz crystal (XT), matching capacitance (C4), clock accuracy is adjusted electric capacity (C1), (C2), (C3) and peripheral components diode (D1), (D2), capacitor (C5), resistor (R1), (R2) form the clock unit circuit, clock output optocoupler (GL), resistor (R3), (R4), (R5) and triode (BG) form clock frequency output unit circuit, it is characterized in that: also comprise one by thermistor (RT), precision resister (R6) is formed temperature sensor circuit, above-mentioned all devices all are welded on formation package module in back on the pcb board, and external interface causes on the single looper of 8 cores.

2, the clock module of band temperature sensor as claimed in claim 1, it is characterized in that: in the temperature sensor circuit of forming by thermistor (RT), precision resister (R6), thermistor (RT) is connected with precision resister (R6), its series connection end is connected with the single looper of 8 cores as the output (ADT) of temperature sensor circuit, the two ends of series circuit respectively with module in the positive pole (VDD) of working power be connected with negative pole (VSS).