TWI393318B - Electrical circuit protection system and method thereof - Google Patents

Description

Circuit protection device and method thereof

The present invention relates to a protection device and method thereof, and more particularly to a circuit protection device and method therefor.

In a circuit system, when power is supplied to a circuit device as power required for the operation of the device, it is necessary to face the problem that the current of the circuit device is excessive and the circuit components are overheated. In the prior art, the overheating of circuit components mainly comes from the fact that the supplied current exceeds a set critical value, causing the heat of the component to rise rapidly. The solution is to determine whether the current supplied to the circuit device exceeds a critical value when the current exceeds At this critical value, the overload protection device is activated. That is to say, the activation of the overload protection device is controlled by the current limiting circuit, and the disadvantage is that when the current is still in the normal range, the temperature of the circuit device has already exceeded the temperature threshold, that is, only According to whether the current exceeds the critical value to judge the overheating state, the overheating state cannot be detected in time and correctly, and the circuit device is liable to malfunction due to overheating. Therefore, it is necessary to improve the conventional circuit protection device.

It is an object of the present invention to provide a circuit protection device and method thereof for resolving whether a circuit system accurately detects whether the circuit system is overheated before or after the current exceeds a threshold.

To achieve the above object, the present invention provides a circuit protection device and a method thereof, the circuit protection device including a processing unit, a temperature detecting unit, a current detecting unit, a first switching switch (SW1), and a second switching switch (SW2). The processing unit is configured to control the host system to supply a power signal (SP) to the first circuit. In an embodiment, the processing unit controls the host system to provide a voltage signal to the first circuit, for example, according to a universal serial bus (USB) protocol. The temperature detecting unit detects a first temperature (T1) of the first circuit to determine whether the first temperature (T1) exceeds a temperature threshold (T_TH), when the first temperature of the first circuit (T1) When the temperature is less than the threshold value (T_TH), the power signal (SP) is transmitted to drive the second circuit, and when the second circuit is electrically connected to the first circuit, the temperature detecting unit determines the first circuit. Whether one of the first temperature (T1) and the second temperature (T2) of the second circuit exceeds the temperature threshold (T_TH).

When the first temperature (T1) of the first circuit exceeds the temperature threshold (T_TH), the processing unit controls the host system to cut off the power signal (SP) supplied to the first circuit. And when one of the first temperature (T1) of the first circuit and the second temperature (T2) of the second circuit exceeds the temperature threshold (T_TH), and when the second circuit is electrically connected to In the first circuit, the processing unit cuts off the power signal (SP) supplied by the first circuit to the second circuit.

When the first temperature (T1) of the first circuit and the second temperature (T2) of the second circuit are small When the temperature threshold (T_TH) is reached, the current detecting unit detects a current signal corresponding to the power signal to determine whether the current signal exceeds a current threshold (I_TH), when the current signal (SI) When the current threshold value (I_TH) is less than, the temperature detecting unit continuously determines whether one of the first temperature (T1) and the second temperature (T2) exceeds the temperature threshold (T_TH).

The circuit protection method of the present invention comprises the following steps:

(a) The circuit protection device controls the host system to supply a power signal to the first circuit.

(b) activating the temperature detecting unit to detect a first temperature of the first circuit.

(c) The temperature detecting unit determines whether the first temperature of the first circuit exceeds a temperature threshold.

(d) when the first temperature of the first circuit is less than the temperature threshold, the second circuit is electrically connected to the first circuit, and the power signal is transmitted through the first circuit to drive the second circuit.

(e) when the first temperature of the first circuit is less than the temperature threshold, the temperature detecting unit determines whether the first temperature of the first circuit and a second temperature of the second circuit are both Exceed this temperature threshold.

(f) When the first temperature of the first circuit and the second temperature of the second circuit are less than the temperature threshold, the current detecting unit detects a current signal corresponding to the power signal.

(g) The current detecting unit determines whether the current signal exceeds a current threshold, and when the current signal does not exceed the current threshold, returns to step (e).

In order to make the above-mentioned contents of the present invention more comprehensible, the preferred embodiments are described below, and the detailed description is as follows:

Referring to FIG. 1 , there is shown a circuit having a circuit protection device 100 in accordance with an embodiment of the present invention. Road system 102 block diagram. The circuit protection device 100 is connected to a host system 104 to the first circuit 106, and the first circuit 106 is selectively connected to the second circuit 108. The circuit protection device 100 includes a processing unit 110, a temperature detecting unit 112, and current detection. The unit 114, the first changeover switch (SW1) 116, and the second changeover switch (SW2) 118. The processing unit 110 is coupled to the host system 104, the first circuit 106, the second circuit 108, the temperature detecting unit 112, and the current detecting unit 114. The temperature detecting unit 112 is coupled to the The first circuit 106 and the second circuit 108 are respectively coupled to the first circuit 106 and the second circuit 108; the first switch (SW1) 116 is disposed on the host system 104 and the The first switch 106 (SW2) 118 is disposed between the first circuit 106 and the second circuit 108. In an embodiment, the first circuit 106 is, for example, a card reader or a hub having a power supply function; when the first circuit 106 is a card reader, the second circuit 108 is, for example, It is a variety of memory cards, such as a secure digital card (SD card), a MS memory card (Memory Stick Card), a CF memory card (Compact Flash Card) or an MMC memory card (Multi-Media). When the first circuit 106 is a hub, the second circuit 108 is, for example, a control line disposed in the hub.

The processing unit 110 is configured to control the host system 104 to supply a power signal (SP) to the first circuit 106. In an embodiment, the processing unit 110 controls the host system 104 by using a first voltage enable signal (EN_V1). A first switch (SW1) 116 is connected to the first circuit 106. The processing unit 110 controls the host system 104 to provide a voltage signal to the first circuit 106, for example, according to a universal serial bus (USB) protocol. The temperature detecting unit 112 detects the first temperature (T1) of the first circuit 106 to determine whether the first temperature (T1) exceeds a temperature threshold (T_TH), wherein the processing unit 110 uses temperature, for example. Signal (EN_T) control The activation of the temperature detecting unit 112 is performed to determine whether to start the detection of the first temperature (T1). When the first temperature (T1) of the first circuit 106 is less than the temperature threshold (T_TH), the power signal (SP) is transmitted to the second circuit 108 via the first circuit 106. When the first temperature (T1) of the first circuit 106 is greater than the temperature threshold (T_TH), the processing unit 110 controls the host system 104 to switch the first switch (SW1) 116 to cut off the supply to the first A power signal (SP) of a circuit 106.

When the second circuit 108 is electrically connected to the first circuit 106, the temperature detecting unit 112 determines the first temperature (T1) of the first circuit 106 and the second temperature (T2) of the second circuit 108. Whether one of them exceeds the temperature threshold (T_TH). The processing unit 110 switches the first circuit 106 when one of the first temperature (T1) of the first circuit 106 and the second temperature (T2) of the second circuit 108 exceeds the temperature threshold (T_TH). a second switch (SW2) 118 between the second circuit 108 and the power signal (SP) supplied to the second circuit 108 by the first circuit 106, for example, using a second voltage enable signal (EN_V2) The second switch (SW2) 116 is controlled.

When the second circuit 108 is electrically connected to the first circuit 106, and when the first temperature (T1) of the first circuit 106 and the second temperature (T2) of the second circuit 108 are less than the temperature threshold ( When T_TH), the current detecting unit 114 detects a current signal corresponding to the power signal (SP) to determine whether the current signal exceeds a current threshold (I_TH), when the current signal is less than the current threshold. (I_TH), the temperature detecting unit 112 continuously determines whether one of the first temperature (T1) and the second temperature (T2) exceeds the temperature threshold (T_TH).

When the current signal exceeds the current threshold (I_TH), the processing unit 110 switches the first switch (SW1) 116 between the host system 104 and the first circuit 106 to cut off the first The circuit 106 supplies a power signal (SP) to the second circuit 108. In one embodiment, the current detecting unit 114 calculates a current duration of the current signal when the current signal exceeds the current threshold (I_TH), and determines that the current signal exceeds the current threshold (I_TH). Whether the current duration exceeds a duration threshold, and the current duration when the current signal exceeds the current threshold (I_TH) exceeds the duration threshold, the processing unit 110 switches the first circuit 106 and the second A second switch (SW2) 118 between the circuits 108 to cut off the power signal (SP) supplied by the first circuit 106 to the second circuit 108. In addition, the processing unit 110 reports the first temperature (T1) of the first circuit 106, the second temperature (T2) of the second circuit 108, and the current signal to the host system 104 to detect the temperature and current state of the circuit. .

According to the above, the circuit protection device 100 of the present invention uses the processing unit 110 to synchronously control the temperature detecting unit 112 and the current detecting unit 114, mainly detecting the first circuit 106 and/or the second circuit 108 according to the temperature detecting unit 112. The temperature is determined such that the current detecting unit 114 determines whether to detect the current according to the detection result of the temperature and determines whether the first circuit 106 supplies power to the second circuit 108, thereby effectively avoiding overload or overheating of the circuit system. (overheat) phenomenon. In particular, after the first circuit 106 receives the power from the host system 104 and after the first circuit 106 supplies the power to the second circuit 108, the first temperature (T1) and the second temperature (T2) are correctly detected, and Before the first circuit 106 supplies power to the second circuit 108, it effectively solves the problem that the circuit system overheats before and after the current threshold is exceeded.

Referring to Figures 1 and 2, a second block diagram of a circuit protection device 100 in accordance with a first embodiment of the present invention is shown. The processing unit 110 is coupled to the temperature detecting unit 112 and the current detecting unit 114 respectively. The temperature detecting unit 112 includes a decoder 200, a temperature sensor 202, and a comparator 204. The decoder 200 is coupled to the processing unit 110 and the comparator. The comparator 204 is coupled to the temperature sensor 202, the processing unit 110, and the decoder 204. The decoder 200 is configured to parse a temperature setting signal (T_SEL) to form the temperature threshold (T_TH). In an embodiment, the temperature setting signal (T_SEL) is, for example, a 2-bit signal. The bit combination represents a temperature set value, and the decoder 200 parses the 2-bit signal to form a set of four temperature thresholds. The temperature sensor 202 is configured to sense the first temperature (T1) of the first circuit 106. The comparator 204 is configured to compare the first temperature (T1) of the first circuit 106 and the second temperature (T2) of the second circuit 108 and the temperature threshold (T_TH), respectively. In one embodiment, the temperature sensor 202 converts the first temperature (T1) and the second temperature (T2) into a voltage value, and the comparator 204 compares the voltage value with the temperature threshold (T_TH). The size of the corresponding voltage value.

The current detecting unit 114 includes a current sensor 206 and a timer 208. The current sensor is coupled to the first circuit 106 , the second circuit 108 , and the timer 208 . The timer 208 is coupled to the current sensor 206 to the processing unit 110 . The current sensor 206 senses the current signal corresponding to the power signal (SP). The timer 208 is configured to detect a current duration of the current signal when the current signal exceeds the current threshold (I_TH). The processing unit 110 controls the timer 208 to determine whether the current duration when the current signal exceeds the current threshold (I_TH) exceeds a duration threshold, when the current signal exceeds the current threshold (I_TH) The current protection duration exceeds the duration threshold, and the circuit protection device 100 turns off the power signal (SP) supplied by the first circuit 106 to the second circuit 108. When the current signal exceeds the current threshold (I_TH), the current duration does not exceed the duration threshold, and the current detecting unit 114 resets the current signal when the current signal exceeds the current threshold (I_TH) Current duration.

Referring to Figures 1-3, Figure 3 is a flow chart showing a method of performing circuit protection in accordance with an embodiment of the present invention. The circuit protection device 100 is applied to the circuit protection device 100. The circuit protection device 100 is connected to the host system 104 to the first circuit 106. The circuit protection device 100 includes the processing unit 110, the temperature detecting unit 112, and the current detecting unit 114. The first switching switch (SW1) 116 and the second switching switch (SW2) 118, the current detecting unit 114 is connected to the first circuit 106 to the second circuit 108. The circuit protection method comprises the following steps: In step S300, the circuit protection device 100 controls the host system 104 to supply a power signal (SP) to the first circuit 106. In an embodiment, the processing unit 110 controls the first switch (SW1) 116 between the host system 104 and the first circuit 106 by using a first voltage enable signal (EN_V1).

In step S302, the temperature detecting unit 112 is activated to detect the first temperature (T1) of the first circuit 106. For example, the temperature activation signal (EN_T) is used to control the activation of the temperature detecting unit 112 to determine whether to start the detection of the first temperature (T1).

In step S304, when the second circuit 108 is not electrically connected to the first circuit 106, the temperature detecting unit 112 determines whether the first temperature (T1) of the first circuit 106 exceeds a temperature threshold (T_TH). ).

In step S306, when the first temperature (T1) of the first circuit 106 is less than the temperature threshold (T_TH), the second circuit 108 is electrically connected to the first circuit 106, and is transmitted via the first circuit 106. The power signal (SP) drives the second circuit 108. As shown in step S307, when the first temperature (T1) of the first circuit 106 exceeds the temperature threshold (T_TH), the processing unit 110 controls the host system 104 to switch the first switch (SW1) 116, To cut off the power signal (SP) supplied to the first circuit 106.

In step S308, when the second circuit 108 is electrically connected to the first circuit 106, the temperature detecting unit 112 determines a first temperature (T1) of the first circuit 106 and a second of the second circuit 108. Whether one of the temperatures (T2) exceeds the temperature threshold (T_TH).

In step S310, when the first temperature (T1) of the first circuit 106 and the second temperature (T2) of the second circuit 108 are less than the temperature threshold (T_TH), the current detecting unit 114 detects The current signal corresponding to the power signal (SP) is measured. As shown in step S320, when one of the first temperature (T1) of the first circuit 106 and the second temperature (T2) of the second circuit 108 exceeds the temperature threshold (T_TH), the process The unit 110 switches the second switch (SW2) 118 between the first circuit 106 and the second circuit 108 to cut off the power signal (SP) supplied by the first circuit 106 to the second circuit 108, for example, by utilizing The second voltage enable signal (EN_V2) controls the second switch (SW2) 118.

In step S312, the current detecting unit 114 determines whether the current signal exceeds a current threshold (I_TH). When the current signal does not exceed the current threshold (I_TH), the process returns to step S308, that is, the first Whether one of the first temperature (T1) of the circuit 106 and the second temperature (T2) of the second circuit 108 exceeds the temperature threshold (T_TH), otherwise step S314 is performed.

In step S314, when the current signal exceeds the current threshold (I_TH), the current detecting unit 114 calculates the current duration of the current signal.

In step S316, the processing unit 110 determines whether the current duration exceeds a duration threshold. As shown in step S320, when the current duration exceeds the duration threshold, the processing unit 110 switches the second switch (SW2) 118 between the first circuit 106 and the second circuit 108 to cut off the The first circuit 106 supplies a power signal (SP) to the second circuit 108.

In step S318, when the current duration does not exceed the duration threshold, the current detecting unit 114 resets the current duration of the current signal, and returns to step S310, that is, the current detecting unit 114 continues to detect The current signal corresponding to the power signal (SP) is measured.

In step S322, the processing unit 110 reports the first temperature (T1) of the first circuit 106, the second temperature (T2) of the second circuit 108, and the current signal to the host system 104.

According to the above, before the second circuit 108 is electrically connected to the first circuit 106, the temperature detecting unit 112 determines whether the first temperature (T1) of the first circuit 106 exceeds a temperature threshold (T_TH). After the second circuit 108 is electrically connected to the first circuit 106, the temperature detecting unit 112 determines a first temperature (T1) of the first circuit 106 and a second temperature (T2) of the second circuit 108. Whether one of the two exceeds the temperature threshold (T_TH), correctly detecting the first temperature (T1) and the second temperature (T2), effectively solving the problem that the circuit system overheats before and after the current threshold is exceeded. .

While the invention has been described above in terms of the preferred embodiments, the invention is not intended to limit the invention, and the invention may be practiced without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

100‧‧‧Circuit protection device

102‧‧‧Circuit system

104‧‧‧Host system

106‧‧‧First circuit

108‧‧‧Second circuit

110‧‧‧Processing unit

112‧‧‧Temperature detection unit

114‧‧‧current detection unit

116‧‧‧First switch

118‧‧‧Second switch

200‧‧‧Decoder

202‧‧‧temperature sensor

204‧‧‧ Comparator

206‧‧‧ Current Sensor

208‧‧‧Timer

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram showing a circuit system having a circuit protection device in accordance with an embodiment of the present invention.

Figure 2 is a detailed block diagram of a circuit protection device according to Figure 1 of the present invention.

FIG. 3 is a flow chart showing a method of performing circuit protection in accordance with an embodiment of the present invention.

100‧‧‧Circuit protection device

102‧‧‧Circuit system

104‧‧‧Host system

106‧‧‧First circuit

108‧‧‧Second circuit

110‧‧‧Processing unit

112‧‧‧Temperature detection unit

114‧‧‧current detection unit

116‧‧‧First switch

118‧‧‧Second switch

Claims (21)

A circuit protection device is connected to a host system to a first circuit, and the first circuit is selectively electrically connected to a second circuit, the circuit protection device includes: a processing unit coupled to the host system and the The first circuit and the second circuit are configured to control the host system to supply a power signal to the first circuit; a temperature detecting unit is coupled to the processing unit, the first circuit, and the second circuit, respectively Detecting a first temperature of the first circuit to determine whether the first temperature exceeds a temperature threshold. When the first temperature is less than the temperature threshold, transmitting the power signal to drive the second circuit, and when When the second circuit is electrically connected to the first circuit, the temperature detecting unit determines whether one of the first temperature and a second temperature of the second circuit exceeds the temperature threshold; and a current detection The unit is coupled to the processing unit, the first circuit, and the second circuit, and when the first temperature and the second temperature are less than the temperature threshold, the current detecting unit detects the phase A current signal of the power signal is used to determine whether the current signal exceeds a current threshold. When the current signal is less than the current threshold, the temperature detecting unit continuously determines the first temperature and the second temperature. Whether one of the ones exceeds the temperature threshold. The circuit protection device of claim 1, further comprising a first switch coupled between the host system and the first circuit to switch the power signal, and the processing unit utilizes a first The voltage enable signal controls the first switch. The circuit protection device of claim 1, wherein the processing unit controls the host system to cut off the supply to the first circuit when the first temperature of the first circuit exceeds the temperature threshold Power signal. The circuit protection device of claim 1, wherein when the first temperature of the first circuit and the second temperature of the second circuit exceed the temperature threshold, and when the When the two circuits are electrically connected to the first circuit, the processing unit cuts off the power signal supplied by the first circuit to the second circuit. The circuit protection device of claim 1, further comprising a second switch coupled between the first circuit and the second circuit to switch the power signal, and the processing unit utilizes a first The second voltage enable signal controls the second switch. The circuit protection device of claim 1, wherein the processing unit cuts off the power signal supplied by the first circuit to the second circuit when the current signal exceeds the current threshold. The circuit protection device of claim 1, wherein the current detecting unit calculates a current duration of the current signal when the current signal exceeds the current threshold. The circuit protection device of claim 7, wherein the current detecting unit determines whether the current duration when the current signal exceeds the current threshold exceeds a duration threshold, when the current signal exceeds the current The current duration of the threshold value exceeds the duration threshold, and the processing unit cuts off the power signal supplied by the first circuit to the second circuit. The circuit protection device of claim 1, wherein the temperature detecting unit comprises: a decoder coupled to the processing unit for parsing a temperature setting signal to form the temperature threshold; a sense of temperature a detector for sensing the first temperature and the second temperature; a comparator coupled to the temperature sensor and the decoder for respectively comparing the first temperature of the first circuit and the second temperature of the second circuit to a magnitude of the temperature threshold. The circuit protection device of claim 1, wherein the current detecting unit comprises: a current sensor coupled to the first circuit to sense the current signal corresponding to the power signal; And a timer coupled to the processing unit for detecting a current duration of the current signal. The circuit protection device of claim 10, wherein the processing unit controls the timer to determine whether the current duration when the current signal exceeds the current threshold exceeds a duration threshold, when the current The processing unit cuts off the power signal supplied by the first circuit to the second circuit for a duration exceeding the duration threshold. The circuit protection device of claim 11, wherein when the current signal exceeds the current threshold, the current duration does not exceed the duration threshold, the current detecting unit resets the current signal. The current duration, and the current detecting unit continuously calculates the current duration of the current signal. A circuit protection method is applicable to a circuit protection device, wherein the circuit protection device is connected to a host system to a first circuit, the circuit protection device includes a temperature detecting unit and a current detecting unit, and the first circuit is selectively connected In a second circuit, the circuit protection method includes the following steps: (a) the circuit protection device controls the host system to supply a power signal to the first circuit; (b) activating the temperature detecting unit to detect a first temperature of the first circuit; (c) the temperature detecting unit determines whether the first temperature of the first circuit exceeds a temperature threshold; When the first temperature of the first circuit is less than the temperature threshold, the second circuit is electrically connected to the first circuit, and the power signal is transmitted through the first circuit to drive the second circuit; (e) When the first temperature of the first circuit is less than the temperature threshold, the temperature detecting unit determines whether one of the first temperature of the first circuit and a second temperature of the second circuit exceeds the temperature threshold (f) when the first temperature of the first circuit and the second temperature of the second circuit are less than the temperature threshold, the current detecting unit detects a current signal corresponding to the power signal; And (g) the current detecting unit determines whether the current signal exceeds a current threshold, and when the current signal does not exceed the current threshold, returns to step (e). The circuit protection method of claim 13, wherein in the step (a), the processing unit switches the power signal by using a first voltage-enabled signal. The circuit protection method of claim 13, wherein in the step (c), when the first temperature of the first circuit exceeds the temperature threshold, the circuit protection device controls the host system to cut off the supply The power signal to the first circuit. The circuit protection method of claim 13, wherein in step (e), one of the first temperature of the first circuit and the second temperature of the second circuit exceeds the temperature threshold The processing unit cuts off the power signal supplied by the first circuit to the second circuit. For the circuit protection method described in claim 16 of the patent scope, in step (e), the The control unit switches the power signal by using a second voltage enable signal. The circuit protection method of claim 13, wherein in the step (g), when the current signal exceeds the current threshold, the processing unit cuts off the first circuit supply by using a second voltage enable signal. The power signal to the second circuit. The circuit protection method of claim 13, wherein in the step (g), the method further comprises the following steps: (g1) the current detecting unit calculates one of the current signals when the current signal exceeds the current threshold a current duration; and (g2) determining whether the current duration when the current signal exceeds the current threshold exceeds a duration threshold, and the current duration exceeds the duration when the current signal exceeds the current threshold The threshold value is that the processing unit cuts off the power signal supplied by the first circuit to the second circuit. The circuit protection method of claim 19, in step (g2), when the current duration does not exceed the duration threshold, the current detecting unit resets the current duration of the current signal, And the current detecting unit continuously calculates the current duration of the current signal. The circuit protection method of claim 13, after the step (g), further comprising the step (h): the processing unit returns the first temperature of the first circuit, the second of the second circuit The temperature and the current signal to the host system.