CN104716922B - Electronic device - Google Patents

Abstract

The present invention provides a kind of electronic device, it includes crystal oscillator, data processor, switching switch and matching network, the crystal oscillator has an actual loading capacitance, the matching network for changing crystal oscillator actual loading capacitance, the switching switch is electrically connected between crystal oscillator and data processor, the data processor is used to detect the actual loading capacitance of crystal oscillator, and controls switching switch and matching network ON/OFF according to the actual loading capacitance.The electronic device can change the actual loading capacitance of crystal oscillator, so as to shorten debug time, reduce the R&D cycle.

Description

Electronic device

Technical field

The present invention relates to a kind of electronic device more particularly to a kind of electronic devices for the load capacitance that can adjust crystal oscillator.

Background technique

Crystal oscillator is widely used in the oscillating circuit of all kinds of electronic devices such as mobile phone, computer, remote controler, for electronics The data processor of device provides clock signal.However, causing since there are errors for the load capacitance of crystal oscillator in electronic device In initial stage debugging process, it may appear that the phenomenon that failure (AFC Calibration Fail) is calibrated in automatic frequency control.

Summary of the invention

In view of the foregoing, it is necessary to which a kind of electronic device of load capacitance that can adjust crystal oscillator is provided.

A kind of electronic device comprising crystal oscillator, data processor, switching switch and matching network, the crystal oscillator are real with one Border load capacitance value, switching switch are electrically connected between crystal oscillator and data processor, the matching network for changing The actual loading capacitance of crystal oscillator, the data processor are used to detect the actual loading capacitance of crystal oscillator, and according to the reality Load capacitance value control switching switch and matching network ON/OFF.

A kind of electronic device comprising crystal oscillator, data processor, switching switch and matching network, the crystal oscillator are real with one Border load capacitance value, the switching switch selectively ON/OFF matching network, and the matching network is for changing crystal oscillator Actual loading capacitance, the data processor preset a load capacitance value section, and the data processor passes through switching switch It is electrically connected with crystal oscillator, for detecting the actual loading capacitance of crystal oscillator, when the actual loading capacitance falls into load capacitance value When section, the data processor controlled switching switch disconnects matching network and the crystal oscillator and matching network is disconnected, when this When actual loading capacitance is located at outside load capacitance value section, the data processor controlled switching switch conduction matching network makes It obtains the crystal oscillator and matching network is electrically connected.

The data processor of above-mentioned electronic device passes through the actual loading capacitance of detecting crystal oscillator, and according to the actual negative Carry capacitance control switching switch, and then ON/OFF matching network.When switching switch is connected with matching network, crystal oscillator Actual loading capacitance is changed, and the actual loading capacitance after change complies with standard.In this way, in the early stage in debugging process, The phenomenon that being not in automatic frequency control calibration failure (AFC Calibration Fail), so as to shorten debug time, subtract Few R&D cycle.

Detailed description of the invention

Fig. 1 is the circuit diagram of the electronic device of present pre-ferred embodiments.

Main element symbol description

Electronic device	100
		Crystal oscillator	10
Switching switch	20
		Power pins	VDD
Grounding pin	GND
		Control pin	Ctrl
First data pin	P1
		Second data pin	P2
Third data pin	P3
		Power supply	VCC
Data processor	30
		Input and output pin	GPIO
Crystal oscillator pin	XTAL
		Matching network	40
Inductance	L
		First capacitor	C1
Second capacitor	C2

The present invention that the following detailed description will be further explained with reference to the above drawings.

Specific embodiment

Referring to Fig. 1, presently preferred embodiments of the present invention provides a kind of electronic device 100, can be helped for mobile phone, individual digital Manage (PDA), tablet computer etc..

The electronic device 100 includes crystal oscillator 10, switching switch 20, data processor 30 and matching network 40.The switching is opened It closes 20 to be electrically connected between crystal oscillator 10 and data processor 30, and selectively ON/OFF matching network 40.

The crystal oscillator 10 is used to provide clock signal for data processor 30, in the present embodiment, the output frequency of the crystal oscillator For 26MHz, theoretical duty capacitance is 7.5pf.

The switching switch 20 is used under the control of data processor 30, with 40 ON/OFF of matching network.Specifically, The switching switch 20 includes power pins VDD, grounding pin GND, control pin Ctrl, the first data pin P1, the second data Pin P2 and third data pin P3.A power pins VDD and power supply VCC is electrically connected, grounding pin GND ground connection, should It controls pin Ctrl and data processor 30 is electrically connected, the first data pin P1 and crystal oscillator 10 are electrically connected, second number It is electrically connected according to pin P2 and data processor 30, the third data pin P3 and matching network 40 are electrically connected.

Also, the first data pin P1 and the second data pin P2 is electrically connected, which is used for Under the control for controlling pin Ctrl, with the first data pin P1 and the second data pin P2 ON/OFF.Specifically, work as control When pin Ctrl receives high level signal, third data pin P3 and the first data pin P1 and the second data pin P2 is controlled Conducting, switches switch 20 at this time and matching network 40 is connected.When control pin Ctrl receives low level signal, third is controlled Data pin P3 and the first data pin P1 and the second data pin P2 is disconnected, and switches switch 20 at this time and matching network 40 is disconnected It opens.

The data processor 30 is used to detect the actual loading capacitance of crystal oscillator 10, and according to the actual loading capacitance control System switching switch 20.Specifically, which includes universal input output pin GPIO and crystal oscillator pin XTAL.This is logical It is electrically connected with the control pin Ctrl of input and output pin GPIO and switching switch 20.The crystal oscillator pin XTAL and switching switch 20 the second data pin P2 is electrically connected, to be electrically connected by the switching switch 20 and crystal oscillator 10, with defeated to crystal oscillator 10 A calibration signal out then detects the actual loading capacitance of crystal oscillator 10.The also default load capacitance of the data processor 30 It is worth section, when the actual loading capacitance falls into load capacitance value section, input and output pin GPIO exports low level letter Number, when the actual loading capacitance is located at outside load capacitance value section, input and output pin GPIO exports high level signal.

The matching network 40 for changing crystal oscillator 10 actual loading capacitance.In the present embodiment, the matching network 40 Including inductance L, first capacitor C1 and the second capacitor C2.Inductance L is electrically connected at the third data pin P3 of switching switch 20 Between ground, first capacitor C1 and the second capacitor C2 are parallel to the both ends of inductance L, and first capacitor C1 and the second capacitor C2 One end is grounded.Since the matching network 40 is electrically connected by switching switch 20 and crystal oscillator 10, impedance matching can be passed through Mode changes the actual loading capacitance of crystal oscillator 10.Also, pass through the inductance value and first capacitor C1 and second of trimming inductance L The capacitance of capacitor C2, the impedance matching of the adjustable matching network 40, so that the actual loading after the change of crystal oscillator 10 Capacitance is close to theoretical duty capacitance.

The working principle of the electronic device 100 is further illustrated below, when electronic device 100 is in initial stage debugging process In, data processor 30 exports calibration signal to crystal oscillator 10 by crystal oscillator pin XTAL, to detect the actual loading of crystal oscillator 10 Capacitance.The actual loading capacitance is compared the data processor 30 with preset load capacitance value section, when the reality When border load capacitance value falls into load capacitance value section, input and output pin GPIO exports low level signal, controls pin Ctrl controls third data pin P3 and the first data pin P1 and the second data pin P2 and disconnects, and switches switch 20 and pair net Network 40 disconnects.At this point, the actual loading capacitance due to crystal oscillator 10 falls into load capacitance value section, the output frequency of the crystal oscillator 10 Meet the requirement of data processor 30, to debug by initial stage.

When the actual loading capacitance is located at outside load capacitance value section, input and output pin GPIO exports high level Signal, control pin Ctrl control third data pin P3 are connected with the first data pin P1 and the second data pin P2, switch Switch 20 and matching network 40 are connected.At this point, matching network 40 changes the actual loading of crystal oscillator 10 by way of impedance matching Capacitance, so that the actual loading capacitance after the change falls into load capacitance value section, thus in the early stage in debugging process, no The phenomenon that will appear automatic frequency control calibration failure (AFC Calibration Fail).

The data processor 30 of electronic device 100 of the invention is by output calibration signal, to detect the reality of crystal oscillator 10 Border load capacitance value, and switching switch 20, and then ON/OFF matching network 40 are controlled according to the actual loading capacitance.When When switching switch 20 and the conducting of matching network 40, the actual loading capacitance of crystal oscillator 10 is changed, and the actual loading after change Capacitance complies with standard.In this way, being not in automatic frequency control calibration failure (AFC in the early stage in debugging process Calibration Fail) the phenomenon that, so as to shorten debug time, reduce the R&D cycle.

Claims (8)

1. a kind of electronic device comprising crystal oscillator and data processor, the crystal oscillator have an actual loading capacitance, and feature exists In: the electronic device further includes switching switch and matching network, and the switching switch is electrically connected at crystal oscillator and data processor Between, switching switch selectively ON/OFF matching network, the matching network for changing crystal oscillator actual loading Capacitance, the data processor are used to detect the actual loading capacitance of crystal oscillator, the default load electricity of the data processor Capacitance section, the data processor is electrically connected by switching switch with crystal oscillator, for detecting the actual loading capacitor of crystal oscillator Value, when the actual loading capacitance falls into load capacitance value section, the data processor controlled switching switch disconnects matching Network disconnects the crystal oscillator and matching network, described when the actual loading capacitance is located at outside load capacitance value section Data processor controlled switching switch conduction matching network is electrically connected the crystal oscillator and matching network.

2. electronic device as described in claim 1, it is characterised in that: the switching switch includes the first data pin and second Data pin, first data pin and crystal oscillator are electrically connected, and second data pin and data processor are electrically connected, and First data pin and the second data pin are electrically connected.

3. electronic device as claimed in claim 2, it is characterised in that: the data processor includes crystal oscillator pin, the crystalline substance The pin that shakes is electrically connected with the second data pin that switching switchs, and to export a calibration signal to crystal oscillator, then detects crystal oscillator Actual loading capacitance.

4. electronic device as claimed in claim 3, it is characterised in that: the switching switch includes control pin, the data Processor includes universal input output pin, and the control pin of the universal input output pin and switching switch is electrically connected.

5. electronic device as claimed in claim 4, it is characterised in that: when the actual loading capacitance falls into load capacitance value area Between when, universal input output pin export low level signal, when the actual loading capacitance is located at outside load capacitance value section, Universal input output pin exports high level signal.

6. electronic device as claimed in claim 5, it is characterised in that: the switching switch further includes third data pin, institute It states third data pin to be used under the control of control pin, with the first data pin and the second data pin ON/OFF.

7. electronic device as claimed in claim 6, it is characterised in that: when control pin receives high level signal, control Third data pin is connected with the first data pin and the second data pin, when control pin receives low level signal, control Third data pin processed and the first data pin and the second data pin disconnect.

8. electronic device as claimed in claim 7, it is characterised in that: the matching network includes inductance, first capacitor and Two capacitors, the inductance are electrically connected between the third data pin and ground of switching switch, the first capacitor and the second electricity Hold the both ends for being parallel to inductance, and one end of first capacitor and the second capacitor is grounded.