Bluetooth headset and temperature screening circuit therein

Abstract

The present invention relates to a temperature screening circuit, comprising comparators U1, U2, U3, multi-stage electric control switches SW1, SW2 and two temperature collection points for collecting the voltage output by a temperature sensing device, wherein one temperature collection point is respectively connected to the same direction input end of the comparator U1 and the reverse direction input end of the comparator U2, and the other temperature collection point is respectively connected to the reverse direction input end of the comparator U1 and the same direction input end of the comparator U2; the output end of the comparator U3 is connected to the controlled end of the multi-stage electric control switch SW2, the output ends of the comparators U1 and U2 are respectively connected to the two connection ends of the multi-stage electric control switch SW2, the output end of the multi-stage electric control switch SW2 is connected to the controlled end of the multi-stage electric control switch SW1, and the two temperature collection points are respectively connected to the two connection ends of the multi-stage electric control switch SW1; if the voltage output by the temperature sensing device is negatively correlated with the temperature, the reverse direction input end of the comparator U3 is used to receive the reference voltage, and the same direction input end is connected to the temperature collection point, otherwise the connection method of the input end of the comparator U3 is opposite.

Description

Technical Field

[0001] The invention relates to temperature detection of an earphone battery, and in particular to a Bluetooth earphone and a temperature screening circuit therein. Background Art

[0002] In order to improve the battery life, existing Bluetooth headsets are equipped with batteries on the left and right earphones. In order to realize the battery temperature detection and control function, an NTC resistor is provided on the power supply line of each battery. The Bluetooth chip on the headset detects the voltage on the two NTC resistors respectively to obtain the temperature of the two batteries. When the temperature of any battery exceeds the allowable temperature range, the Bluetooth chip will perform corresponding control, such as charge and discharge control, shutdown control, etc., to realize the protection function.

[0003] In the above structure, the Bluetooth chip needs to consume two detection pins to connect two NTC resistors respectively. Since the pin resources of the Bluetooth chip itself are limited, consuming two detection pins is too luxurious. Therefore, it is urgent to develop a temperature screening circuit to assist the Bluetooth chip in temperature detection in order to save the pin resources of the Bluetooth chip. Summary of the invention

[0004] The present invention improves the deficiencies in the prior art and provides a temperature screening circuit to assist a Bluetooth chip in performing temperature detection, so as to save the Bluetooth chip pin resources.

[0005] To this end, a temperature screening circuit is provided, comprising a comparator U1, a comparator U2, a comparator U3, a multi-stage electric control switch SW1, a multi-stage electric control switch SW2 and two temperature collection points for collecting the output voltages of two temperature sensing devices, wherein one temperature collection point is respectively connected to the same-direction input terminal of the comparator U1 and the reverse input terminal of the comparator U2, and the other temperature collection point is respectively connected to the reverse input terminal of the comparator U1 and the same-direction input terminal of the comparator U2;

[0006] The output ends of the comparators U1 and U2 are respectively connected to the two terminals a2 and b2 of the multi-stage electric-controlled switch SW2, the controlled ends corresponding to the two terminals a2 and b2 of the multi-stage electric-controlled switch SW2 are connected to the output end of the comparator U3, the two terminals a1 and b1 of the multi-stage electric-controlled switch SW1 are respectively connected to the two temperature collection points, and the controlled ends corresponding to the two terminals a1 and b1 of the multi-stage electric-controlled switch SW1 are connected to the common end of the multi-stage electric-controlled switch SW2;

[0007] If the voltage output by the temperature sensing device is negatively correlated with the temperature, the inverting input terminal of the comparator U3 is used to receive the reference voltage, and the non-inverting input terminal is connected to the temperature collection point; otherwise, the non-inverting input terminal of the comparator U3 is used to receive the reference voltage, and the inverting input terminal is connected to the temperature collection point.

[0008] Furthermore, the temperature sensing device is specifically a thermistor.

[0009] Furthermore, the temperature collection point is specifically a voltage dividing contact of a voltage dividing circuit formed by a thermistor.

[0010] Furthermore, the multi-stage electronically controlled switch SW1 and / or the multi-stage electronically controlled switch SW2 is specifically a two-stage electronically controlled switch.

[0011] Furthermore, the input end of the comparator U3 is connected to only one of the temperature collection points.

[0012] A Bluetooth headset is also provided, comprising a Bluetooth chip and the above-mentioned temperature screening circuit, wherein the common end of the multi-stage electric control switch SW1 in the temperature screening circuit is connected to the Bluetooth chip.

[0013] Furthermore, the Bluetooth headset also includes two batteries, and the two temperature sensing devices are specifically used to collect the temperature of the batteries.

[0014] Furthermore, the Bluetooth headset has a left headset and a right headset, and two batteries are respectively placed in the left headset and the right headset.

[0015] Beneficial effects:

[0016] The present invention uses the assistance of the temperature screening circuit, and the Bluetooth chip only uses one detection pin to obtain data of the higher / lower temperature of two temperature sensing devices, thereby achieving the purpose of saving Bluetooth chip pin resources.

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0019] Figure 1 A circuit diagram of a Bluetooth headset of the present invention is shown;

[0020] Figure 2 A circuit diagram of the temperature screening circuit of the present invention is shown. DETAILED DESCRIPTION

[0021] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0022] Example 1

[0023] The Bluetooth headset of this embodiment is as follows Figure 1 As shown, it includes a Bluetooth chip 1, a left earphone 2 and a right earphone 3. Batteries 21 and 31 are respectively placed on the left earphone 2 and the right earphone 3. Voltage divider circuits composed of NTC thermistors are respectively arranged on the power supply lines of the batteries 21 and 31. The voltage divider contacts NTC-R and NTC-L of the two voltage divider circuits are connected to the Bluetooth chip 1 through a temperature screening circuit 6. The voltage divider contacts are used to collect temperature data of the NTC thermistors, so they are called temperature collection points.

[0024] Temperature screening circuit 6 Figure 2 As shown, it is composed of three comparators U1, U2, and U3 plus two two-stage electric control switches SW1 and SW2, wherein the temperature acquisition point NTC-R is respectively connected to the positive input terminal of the comparator U1, the negative input terminal of the comparator U2, and the positive input terminal of the comparator U3, the temperature acquisition point NTC-L is respectively connected to the negative input terminal of the comparator U1 and the positive input terminal of the comparator U2, the output terminal of the comparator U3 is connected to the controlled terminal of the two-stage electric control switch SW2 as a control source, the output terminals of the comparators U1 and U2 are respectively connected to the two wiring terminals a2 and b2 of the two-stage electric control switch SW2, the common terminal com2 of the two-stage electric control switch SW2 is connected to the controlled terminal of the two-stage electric control switch SW1 as another control source, the temperature acquisition points NTC-R and NTC-L are respectively connected to the two wiring terminals a1 and b1 of the two-stage electric control switch SW1, and the common terminal com1 of the two-stage electric control switch SW1 is connected to Figure 1 The Bluetooth chip 1 in it.

[0025] In the following, for the convenience of description, the voltage of the temperature collection point NTC-R is called V NTC-R , the voltage of the temperature collection point NTC-L is called V NTC-L , the reference voltage is called V REF .

[0026] See Figure 2 When using, first convert the reference temperature into V REF , V REF Input to the inverting input of comparator U3, then:

[0027] When V NTC-R <V REFWhen V NTC-R >V NTC-L , the comparator U2 outputs a low level, so that the connection terminal b1 of the two-stage electric control switch SW1 is connected to the common terminal com1, and the two-stage electric control switch SW1 outputs V NTC-L , if V NTC-R <V NTC-L , the comparator U2 outputs a high level, so that the connection terminal a1 of the two-stage electric control switch SW1 is connected to the common terminal com1, and the two-stage electric control switch SW1 outputs V NTC-R , it can be seen that in V NTC-R <V REF In this case, the output of the double-stage electric control switch SW1 is V NTC-R With V NTC-L The lower voltage value among them;

[0028] Similarly, when V NTC-R >V REF When V NTC-R >V NTC-L , the comparator U1 outputs a high level, so that the connection terminal a1 of the two-stage electric control switch SW1 is connected to the common terminal com1, and the two-stage electric control switch SW1 outputs V NTC-R , if V NTC-R <V NTC-L , the comparator U1 outputs a low level, so that the connection terminal b1 of the two-stage electric control switch SW1 is connected to the common terminal com1, and the two-stage electric control switch SW1 outputs V NTC-L , it can be seen that in V NTC-R >V REF In this case, the output of the double-stage electric control switch SW1 is V NTC-R With V NTC-L The higher voltage value.

[0029] Since the resistance of the NTC thermistor is inversely proportional to the temperature, and the voltage of the NTC thermistor is directly proportional to its resistance, this means that the higher the temperature, the lower the voltage of the NTC thermistor.

[0030] When V NTC-R <V REF When the temperature of the NTC thermistor corresponding to the temperature collection point NTC-R is higher than the reference temperature, the two-stage electric control switch SW1 outputs V NTC-R With VNTC-L The lower voltage value means that the temperature screening circuit automatically selects the one with higher temperature from the two NTC thermistors for detection by the Bluetooth chip. The Bluetooth chip can then determine whether the temperature is higher than the upper limit based on the higher temperature.

[0031] When V NTC-R >V REF When the temperature of the NTC thermistor corresponding to the temperature collection point NTC-R is lower than the reference temperature, the two-stage electric control switch SW1 outputs V NTC-R With V NTC-L The higher voltage value means that the temperature screening circuit automatically selects the one with lower temperature from the two NTC thermistors for detection by the Bluetooth chip. The Bluetooth chip can then determine whether the temperature is below the allowable lower limit based on the lower temperature.

[0032] In this way, with the assistance of the temperature screening circuit, the Bluetooth chip can obtain the data of the higher / lower temperature of the two NTC thermistors with only one detection pin, and then make a judgment based on the higher / lower data, thereby realizing the temperature detection control function in the prior art and achieving the purpose of saving Bluetooth chip pin resources.

[0033] It should be noted that:

[0034] Other temperature sensing devices such as temperature sensors can be used to replace NTC thermistors to implement the temperature detection function. Since other temperature sensing devices such as temperature sensors are all existing technologies, their circuit structures are not described here. When other temperature sensing devices are selected to detect temperature, the output end of the other temperature sensing devices is the temperature collection point.

[0035] A multi-stage electric control switch can be used to replace the two-stage electric control switch. The specific connection method is referred to the connection method of the two-stage electric control switch, which will not be described in detail here.

[0036] Example 2

[0037] Embodiment 2 is based on Embodiment 1, and the positive input terminal of the comparator U3 is changed to be connected to the temperature collection point NTC-L, so as to realize the function of the temperature screening circuit in Embodiment 1.

[0038] It should be noted that, as a secondary option, the positive input terminal of the comparator U3 can be changed to be connected to the temperature collection points NTC-R and NTC-L respectively, so that the temperature collection points NTC-R and NTC-L can control the output of the comparator U3. However, this option will cause the output level of the comparator U3 to jump quickly, increasing power loss, so it can be selected according to actual needs.

[0039] Example 3

[0040] Example 3 Based on Example 1, the NTC thermistor is replaced by a PCT thermistor, and the negative input terminal of the comparator U3 is changed to connect the PCT thermistor, and the positive input terminal of the comparator U3 is changed to input the reference voltage V REF , and the function of the temperature screening circuit in Example 1 is also realized.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, rather than to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present application.

Claims

1. A temperature screening circuit, characterized in that: It includes a comparator U1, a comparator U2, a comparator U3, a multi-stage electric control switch SW1, a multi-stage electric control switch SW2 and two temperature collection points for collecting the output voltages of two temperature sensing devices, wherein one of the temperature collection points is respectively connected to the same-direction input end of the comparator U1 and the reverse input end of the comparator U2, and the other temperature collection point is respectively connected to the reverse input end of the comparator U1 and the same-direction input end of the comparator U2; The output ends of the comparators U1 and U2 are respectively connected to the two terminals a2 and b2 of the multi-stage electric-controlled switch SW2, the controlled ends corresponding to the two terminals a2 and b2 of the multi-stage electric-controlled switch SW2 are connected to the output end of the comparator U3, the two terminals a1 and b1 of the multi-stage electric-controlled switch SW1 are respectively connected to the two temperature collection points, and the controlled ends corresponding to the two terminals a1 and b1 of the multi-stage electric-controlled switch SW1 are connected to the common end of the multi-stage electric-controlled switch SW2; If the voltage output by the temperature sensing device is negatively correlated with the temperature, the inverting input terminal of the comparator U3 is used to receive the reference voltage, and the non-inverting input terminal is connected to the temperature collection point; otherwise, the non-inverting input terminal of the comparator U3 is used to receive the reference voltage, and the inverting input terminal is connected to the temperature collection point.

2. The temperature screening circuit according to claim 1, characterized in that: The temperature sensing device is specifically a thermistor.

3. The temperature screening circuit according to claim 2, characterized in that: The temperature collection point is specifically a voltage dividing contact of a voltage dividing circuit formed by a thermistor.

4. The temperature screening circuit according to claim 1, characterized in that: The multi-stage electronically controlled switch SW1 and / or the multi-stage electronically controlled switch SW2 are specifically two-stage electronically controlled switches.

5. The temperature screening circuit according to claim 1, characterized in that: The input end of the comparator U3 is connected to only one of the temperature collection points.

6. A Bluetooth headset, including a Bluetooth chip, characterized in that: It also includes the temperature screening circuit according to any one of claims 1 to 5, wherein the common end of the multi-stage electric control switch SW1 in the temperature screening circuit is connected to the Bluetooth chip.

7. The Bluetooth headset according to claim 6, characterized in that: It also includes two batteries, and the two temperature sensing devices are specifically used to collect the temperature of the batteries.

8. The Bluetooth headset according to claim 7, characterized in that: The Bluetooth headset comprises a left headset and a right headset, and two batteries are respectively arranged in the left headset and the right headset.

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