Fault Detection Device, Method and Electronic Device

Abstract

A fault detection device, method and electronic device, the fault detection device comprising: the first detection branch, the input end of which is coupled to N LED strings; the second detection branch, the input end of which is coupled to the N LED strings; the analog-to-digital converter, adapted to convert the input analog voltage into a corresponding digital voltage; the logic control unit, adapted to control the other of the first detection branch and the second detection branch to output the analog voltage on the j-th LED string to be sampled and held when controlling any one of the first detection branch and the second detection branch to sample and hold the analog voltage on the i-th LED string; and determining whether the j-th LED string fails based on the digital voltage. The above solution can improve the detection efficiency of detecting the voltage of the LED string.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and particularly to a fault detection device, method and electronic device. Background Art

[0002] Multi-channel light emitting diode (LED) strings are widely used in fields such as lighting, displays, decoration, and automobiles. Due to the special requirements of LED strings for operating voltage and current, the failure of any one LED may cause the entire LED string to malfunction. Especially in the field of automotive applications, there are strict functional safety requirements, and it is necessary to perform real-time detection on the LED string to determine whether the LED string has failed.

[0003] In the prior art, usually, the analog voltage of a certain LED string is sampled and held first, and the analog voltage is converted into a digital voltage by an analog-to-digital converter (ADC), and the digital voltage is compared with the power supply voltage or the ground terminal. Assuming that the time required to complete a voltage detection of an LED string is T, then T = Tsh + Tconv, where Tsh is the time for one sampling and holding, and Tconv is the time required for the analog-to-digital converter to complete one analog-to-digital conversion. If an electronic device has N LED strings, the time required to complete the voltage detection of the N LED strings is N×T.

[0004] It can be seen that the existing detection method for detecting LED strings has low detection efficiency. Moreover, in some application scenarios, such as in the pulse width modulation (PWM) dimming scenario, since it is necessary to confirm that none of the N LED strings of the electronic device have failed, the minimum pulse of PWM dimming needs to be greater than N×T. Thus, the application scenarios of multi-LED strings are further restricted. Summary of the Invention

[0005] The purpose of the present invention is at least to provide a fault detection device, method and electronic device, which can improve the detection efficiency of detecting the voltage of an LED string.

[0006] In a first aspect, the present invention provides a fault detection device, comprising: a first detection branch, a second detection branch, an analog-to-digital converter, and a logic control unit, wherein: the first detection branch has an input terminal coupled to N LED strings; the second detection branch has an input terminal coupled to the N LED strings; the analog-to-digital converter is adapted to convert an input analog voltage into a corresponding digital voltage; the logic control unit is adapted to control the other of the first detection branch and the second detection branch to output the analog voltage on the j-th LED string to be sampled and held when controlling either the first detection branch or the second detection branch to sample and hold the analog voltage on the i-th LED string; and determine whether the j-th LED string has a fault based on the digital voltage; both i and j are positive integers, and 1 ≤ i ≤ N, 1 ≤ j ≤ N.

[0007] Optionally, the first detection branch includes: a first switch unit, a first capacitor, and N sub-paths, wherein: the first switch unit has a first end coupled to the second ends of the N sub-paths and the first end of the first capacitor, and a second end coupled to the input terminal of the analog-to-digital converter; the first capacitor has a second end grounded; in the N sub-paths, the first end of the i-th sub-path is connected to the i-th LED string, and when the i-th sub-path is turned on, the remaining sub-paths are all turned off.

[0008] Optionally, the i-th sub-path includes an i-th switch unit; the i-th switch unit has a first end coupled to the high side or the low side of the i-th LED string, and a second end coupled to the first end of the first switch unit.

[0009] Optionally, the first detection branch further includes: a first voltage sub-path; the first voltage sub-path has a first end for inputting the power supply voltage and a second end coupled to the first end of the first switch unit.

[0010] Optionally, the second detection branch includes: a second switch unit, a second capacitor, and N sub-paths, wherein: the second switch unit has a first end coupled to the second ends of the N sub-paths and the first end of the second capacitor, and a second end coupled to the input terminal of the analog-to-digital converter; the second capacitor has a second end grounded; in the N sub-paths, the first end of the i-th sub-path is connected to the i-th LED string, and when the i-th sub-path is turned on, the remaining sub-paths are all turned off.

[0011] Optionally, the i-th sub-path includes an i-th switch unit; the i-th switch unit has a first end coupled to the high side or the low side of the i-th LED string, and a second end coupled to the first end of the second switch unit.

[0012] Optionally, the second detection branch further includes: a second voltage sub-path; for the second voltage sub-path, its first end inputs the power supply voltage, and its second end is coupled to the first end of the second switch unit.

[0013] Optionally, the logic control unit is further adapted to receive a control instruction, control the first detection branch to sample and hold the analog electrical signal parameters on the target LED string indicated by the control instruction; and when the second detection branch samples and holds the analog voltage on other LED strings, control the first detection branch to output the analog electrical signal parameters on the target LED string to the analog-to-digital converter; the analog electrical signal parameters include analog voltage or analog current.

[0014] In a second aspect, the present invention further provides a fault detection method, which is applied to any one of the above-mentioned fault detection devices, and includes: when controlling any one of the first detection branch and the second detection branch to sample and hold the analog voltage on the i-th LED string, controlling the other of the first detection branch and the second detection branch to output the analog voltage on the sampled and held j-th LED string.

[0015] In a second aspect, the present invention further provides an electronic device, including any one of the above-mentioned fault detection devices.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0017] The fault detection device includes a first detection branch and a second detection branch. When the first detection branch samples and holds the analog voltage on the i-th LED string, the second detection branch outputs the analog voltage on the sampled and held j-th LED string to the analog-to-digital converter. Correspondingly, when the first detection branch samples and outputs the analog voltage on the i-th LED string to the analog-to-digital converter, the second detection branch can sample and hold the analog voltage on another LED string. Thus, at a certain detection moment, the first detection branch and the second detection branch respectively perform the sampling and holding operation and the voltage output operation, so that the time required for voltage detection of N LED strings can be greatly reduced, the voltage detection efficiency can be improved, and the application scenarios of multiple LED strings can be expanded. Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of a fault detection device in an embodiment of the present invention;

[0019] Figure 2 is a schematic structural diagram of an LED string in an embodiment of the present invention;

[0020] Figure 3 is another schematic structural diagram of an LED string in an embodiment of the present invention. Detailed implementation manners

[0021] As described in the background art, the existing voltage detection method for LED strings has low efficiency and limits the application scenarios of multiple LED strings.

[0022] In an embodiment of the present invention, the fault detection device includes a first detection branch and a second detection branch. When the first detection branch samples and holds the analog voltage on the i-th LED string, the second detection branch outputs the sampled and held analog voltage on the j-th LED string to the analog-to-digital converter. Correspondingly, when the first detection branch samples and outputs the analog voltage on the i-th LED string to the analog-to-digital converter, the second detection branch can sample and hold the analog voltage on another LED string. Thus, at a certain detection moment, the first detection branch and the second detection branch respectively perform the sampling and holding operation and the voltage output operation, so that the time required for voltage detection of N LED strings can be greatly reduced, the voltage detection efficiency can be improved, and the application scenarios of multiple LED strings can be expanded.

[0023] To make the above objects, features, and beneficial effects of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0024] An embodiment of the present invention provides a fault detection device, referring to Figure 1 .

[0025] In an embodiment of the present invention, the fault detection device may include: a first detection branch 101, a second detection branch 102, an analog-to-digital converter 103, and a logic control unit 104, where:

[0026] The first detection branch 101, its input end can be coupled to N LED strings;

[0027] The second detection branch 102, its input end can be coupled to N LED strings;

[0028] The analog-to-digital converter 103 is adapted to convert the input analog voltage into a corresponding digital voltage;

[0029] The logic control unit 104 is adapted to control the other of the first detection branch 101 and the second detection branch 102 to output the sampled and held analog voltage on the j-th LED string to the analog-to-digital converter 103 when controlling either of the first detection branch 101 and the second detection branch 102 to sample and hold the analog voltage on the i-th LED string.

[0030] The logic control unit 104 can also compare the digital voltage corresponding to the analog voltage on the j-th LED string with the power supply voltage or the reference ground terminal to determine whether the j-th LED string has a fault.

[0031] In a specific implementation, both i and j are positive integers, and 1 ≤ i ≤ N, 1 ≤ j ≤ N.

[0032] In an embodiment of the present invention, it is set to perform fault detection on N LED strings during a fault detection time period. At a certain detection moment (such as moment T1) within the fault detection time period, the logic control unit 104 can control the first detection branch 101 to sample and hold the analog voltage on the i-th LED string, and control the second detection branch 102 to output the analog voltage on the j-th LED string that has been sampled and held.

[0033] At the next detection moment (moment T2) within the fault detection time period, the logic control unit 104 can control the first detection branch 101 to output the analog voltage on the i-th LED string that has been sampled and held, and control the second detection branch 102 to sample and hold another LED string (different from the j-th LED string).

[0034] Thus, at any detection moment within the fault detection time period, either the first detection branch 101 or the second detection branch 102 samples and holds the analog voltage on a certain LED string, and the other of the first detection branch 101 and the second detection branch 102 outputs the analog voltage on the LED string that has been sampled and held.

[0035] In a specific implementation, the output end of the first detection branch 101 and the output end of the second detection branch 102 can both be coupled to the input end of the analog-to-digital converter 103. A switch unit can be provided at the output end of the first detection branch 101, and another switch unit can be provided at the output end of the second detection value. When the logic control unit 104 controls the first detection branch 101 to sample and hold the analog voltage on the i-th LED string, the first detection branch 101 disconnects the connection with the input end of the analog-to-digital converter 103; when the logic control unit 104 controls the second detection branch 102 to output the analog voltage on the j-th LED string that has been sampled and held, the second detection branch 102 establishes a connection with the input end of the analog-to-digital converter 103. The first detection branch 101 and the second detection branch 102 are connected to the input end of the analog-to-digital converter 103 in a time-division manner. In other words, the first detection branch 101 and the second detection branch 102 are not connected to the input end of the analog-to-digital converter 103 simultaneously.

[0036] In an embodiment of the present invention, the first detection branch 101 may include: a first switch unit SWA, a first capacitor C1, and N sub-paths, where:

[0037] The first end of the first switch unit SWA is coupled to the second ends of the N sub-paths and is also coupled to the first end of the first capacitor C1; the second end of the first switch unit SWA is coupled to the input end of the analog-to-digital converter 103;

[0038] The second terminal of the first capacitor C1 is grounded;

[0039] Among the N sub-paths, the first end of the i-th sub-path is connected to the i-th LED string, and when the i-th sub-path is conducting, the remaining sub-paths are all disconnected.

[0040] In a specific implementation, the N sub-paths in the first detection unit correspond one-to-one with the N LED strings. Each sub-path may include a switching unit. For the i-th sub-path among the N sub-paths, it includes the i-th switching unit; wherein, the first end of the i-th switching unit is coupled to the high side or the low side of the i-th LED string, and the second end of the i-th switching unit is coupled to the first end of the first switching unit SWA.

[0041] Refer to Figure 2 , a schematic structural diagram of an LED string in an embodiment of the present invention is given. Figure 2 In, an LED string may include M LED lamps, which are LED1, LED2,..., LEDM in sequence. The high side of the LED string may refer to the voltage of the positive electrode of LED1; the low side may refer to the negative electrode of LEDM.

[0042] Such as Figure 2 shown, low-side driving is performed on the LED string, and the driving current source I is coupled between the negative electrode of LEDM and the ground terminal.

[0043] Refer to Figure 3 , a schematic structural diagram of another LED string in an embodiment of the present invention is given. Figure 3 In, high-side driving is performed on the LED string, and the driving current source I is coupled between the power supply voltage VDD and the positive electrode of LED1.

[0044] In a specific implementation, when the i-th sub-path in the first detection branch 101 is conducting, the remaining sub-paths in the first detection branch 101 are all disconnected. When the first switching unit SWA is disconnected, the first capacitor C1 can sample and hold the analog voltage on the i-th LED string; when the first switching unit SWA is closed, the analog voltage sampled and held on the first capacitor C1 (which is the analog voltage on the i-th LED string) is output to the analog-to-digital converter 103.

[0045] In a specific implementation, the first detection branch 101 may further include a first voltage sub-path. The first end of the first voltage sub-path inputs the power supply voltage, and the second end of the first voltage sub-path is coupled to the first end of the first switching unit SWA. The first voltage sub-path may include a switching unit (such as Figure 1The switch unit S0A) therein. When the switch unit is closed, if the first switch unit SWA is open, the first capacitor C1 can sample and hold the power supply voltage; if the first switch unit SWA is closed, the power supply voltage sampled and held in the first capacitor C1 is output to the input terminal of the analog-to-digital converter 103. Thus, the analog-to-digital converter 103 can obtain the digital voltage corresponding to the power supply voltage.

[0046] In the embodiment of the present invention, the second detection branch 102 may include: a second switch unit SWB, a second capacitor C2, and N sub-paths, where:

[0047] The first end of the second switch unit SWB is coupled to the second ends of the N sub-paths and is also coupled to the first end of the second capacitor C2; the second end of the second switch unit SWB is coupled to the input terminal of the analog-to-digital converter 103;

[0048] The second end of the second capacitor C2 is grounded;

[0049] Among the N sub-paths, the first end of the i-th sub-path is connected in series with the i-th LED string, and when the i-th sub-path is turned on, the remaining sub-paths are all turned off.

[0050] In a specific implementation, the N sub-paths in the second detection unit correspond one-to-one with the N LED strings. Each sub-path may include a switch unit. For the i-th sub-path among the N sub-paths, it includes the i-th switch unit; wherein, the first end of the i-th switch unit is coupled to the high side or the low side of the i-th LED string, and the second end of the i-th switch unit is coupled to the first end of the first switch unit SWA.

[0051] In a specific implementation, when the j-th sub-path in the second detection branch 102 is turned on, the remaining sub-paths in the second detection branch 102 are all turned off. When the second switch unit SWB is open, the second capacitor C2 can sample and hold the analog voltage on the j-th LED string; when the second switch unit SWB is closed, the analog voltage sampled and held on the second capacitor C2 (i.e., the analog voltage on the j-th LED string) is output to the analog-to-digital converter 103.

[0052] In a specific implementation, the second detection branch 102 may further include a second voltage sub-path. The first end of the second voltage sub-path inputs the power supply voltage, and the second end of the second voltage sub-path is coupled to the first end of the second switch unit SWB. The second voltage sub-path may include a switch unit (such as Figure 1 the switch unit S0B) therein. When the switch unit is closed, if the second switch unit SWB is open, the second capacitor C2 can sample and hold the power supply voltage; if the third switch unit is closed, the power supply voltage sampled and held in the second capacitor C2 is output to the input terminal of the analog-to-digital converter 103. Thus. The analog-to-digital converter 103 can obtain the digital voltage corresponding to the power supply voltage.

[0053] In an embodiment of the present invention, when the first switch unit SWA is closed, the second switch unit SWB is open. When the first switch unit SWA is open, the second switch unit SWB is closed. Thus, the first detection unit and the second detection unit are not simultaneously coupled to the input terminal of the analog-to-digital converter 103.

[0054] The working principle and process of the fault detection device provided in the above embodiment of the present invention will be described by way of example below.

[0055] In the first detection branch, the switch units on the N sub-paths are S1A, S2A, ……, SNA in sequence. In the second detection branch, the switch units on the N sub-paths are S1B, S2B, ……, SNB in sequence.

[0056] At time T0, in the first detection branch, the switch unit S0A is turned on, the first switch unit SWA is open, and the first capacitor C1 samples and holds the power supply voltage. In the second detection branch, the second switch unit SWB may be in an open state. Alternatively, the second switch unit SWB is closed. At this time, the analog voltage obtained by the analog-to-digital converter is 0.

[0057] At time T1, in the first detection branch, the switch unit S0A is turned off, the first switch unit SWA is closed, and the power supply voltage sampled and held in the first capacitor C1 is output to the analog-to-digital converter. In the second detection branch, the switch unit S1B is turned on, the second switch unit SWB is open, and the second capacitor C2 samples and holds the voltage VLED1 on the first LED string.

[0058] At time T2, in the first detection branch, the switch unit S2A is turned on, the first switch unit SWA is open, and the first capacitor C1 samples and holds the voltage VLED2 on the second LED string. In the second detection branch, the switch unit S1B is turned off, the second switch unit SWB is closed, and the VLED1 sampled and held in the second capacitor C2 is output to the analog-to-digital converter.

[0059] At time T3, in the first detection branch, the switch S2A is turned off, the first switch unit SWA is turned on, and the VLED2 sampled and held in the first capacitor C1 is output to the analog-to-digital converter. In the second detection branch, the switch unit S3B is turned on, the second switch unit SWB is open, and the second capacitor C2 samples and holds the voltage VLED3 on the third LED string.

[0060] And so on, to achieve voltage detection of N LED strings.

[0061] It can be seen that within the fault detection time period, when one of the first detection branch and the second detection branch performs a sample-and-hold operation, the other can output the sampled-and-held analog voltage to the analog-to-digital converter. Therefore, the time required for voltage detection of N LED strings is: N×T / 2. Compared with N×T in the prior art, the time for voltage detection of N LED strings is greatly reduced.

[0062] In the embodiment of the present invention, by using the Figure 1 fault detection device provided above, the first voltage sub-path can also be used to input analog electrical signal parameters, and the analog electrical signal parameters can include the voltage representing the chip temperature, the voltage of a certain pin, the current, etc. Thus, through the above-mentioned fault detection device, the chip temperature can be detected, and the voltage and current of a certain pin can also be detected.

[0063] Thus, while realizing voltage detection of the LED string, detection of other parameters can also be realized.

[0064] It should be noted that in some embodiments, if the capacitance values of the first capacitor C1 / second capacitor C2 are small, then when outputting the sampled-and-held analog voltage to the analog-to-digital converter, the corresponding switch unit can be in a closed state.

[0065] For example, at the above-mentioned T1 moment, in the first detection branch, when the first switch unit SWA is closed, the switch unit S0A continues to be in a conducting state. At the T2 moment, both the first switch unit SWA and the switch unit S0A are disconnected.

[0066] For another example, at the above-mentioned T3 moment, in the first detection branch, the first switch unit SWA is closed, and the switch S2A continues to be in a conducting state.

[0067] The embodiment of the present invention also provides a fault detection method, which is applied to the fault detection device provided in the above embodiment, and includes: within the fault detection time period, when controlling any one of the first detection branch and the second detection branch to sample and hold the analog voltage on the i-th LED string, controlling the other of the first detection branch and the second detection branch to output the sampled-and-held analog voltage on the j-th LED string.

[0068] In a specific implementation, the above-mentioned fault detection method can be executed by the logic control unit 104 in the fault detection device.

[0069] The embodiment of the present invention also provides an electronic device, including the fault detection device provided in any of the above embodiments.

[0070] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A fault detection device, characterized in that: include: A first detection branch, a second detection branch, an analog-to-digital converter, and a logic control unit, wherein: The first detection branch, whose input end is coupled to the N LED strings, comprises: a first switch unit, a first capacitor and N sub-paths, wherein: the first switch unit, whose first end is coupled to the second ends of the N sub-paths and the first end of the first capacitor, and whose second end is coupled to the input end of the analog-to-digital converter; the first capacitor, whose second end is grounded; among the N sub-paths of the first detection branch, the first end of the i-th sub-path is connected to the i-th LED string, and when the i-th sub-path is turned on, the other sub-paths are turned off; The second detection branch, whose input end is coupled to the N LED strings, comprises: a second switch unit, a second capacitor and N sub-paths, wherein: the second switch unit, whose first end is coupled to the second ends of the N sub-paths and the first end of the second capacitor, and whose second end is coupled to the input end of the analog-to-digital converter; the second capacitor, whose second end is grounded; among the N sub-paths of the second detection branch, the first end of the i-th sub-path is connected to the i-th LED string, and when the i-th sub-path is turned on, the other sub-paths are disconnected; The analog-to-digital converter is adapted to convert an input analog voltage into a corresponding digital voltage; A logic control unit, adapted to control the other of the first detection branch and the second detection branch to sample and hold the analog voltage output of the j-th LED string when controlling any one of the first detection branch and the second detection branch to sample and hold the analog voltage on the i-th LED string; judging whether the j-th LED string fails based on the digital voltage; i and j are both positive integers, and 1≤i≤N, 1≤j≤N, and i≠j.

2. The fault detection device according to claim 1, characterized in that: The i-th sub-path includes an i-th switch unit; a first end of the i-th switch unit is coupled to a high side or a low side of the i-th LED string, and a second end of the i-th switch unit is coupled to a first end of the first switch unit.

3. The fault detection device according to claim 1 or 2, characterized in that: The first detection branch further includes: a first voltage sub-path; a first end of the first voltage sub-path is input with a power supply voltage, and a second end of the first voltage sub-path is coupled to the first end of the first switch unit.

4. The fault detection device according to claim 1, characterized in that: The i-th sub-path includes an i-th switch unit; a first end of the i-th switch unit is coupled to a high side or a low side of the i-th LED string, and a second end of the i-th switch unit is coupled to a first end of the second switch unit.

5. The fault detection device according to claim 1 or 4, characterized in that: The second detection branch further includes: a second voltage sub-path; the second voltage sub-path has a first end input with a power supply voltage and a second end coupled to the first end of the second switch unit.

6. The fault detection device according to claim 1, characterized in that: The logic control unit is further adapted to receive a control instruction, control the first detection branch to sample and hold the analog electrical signal parameter on the target LED string indicated by the control instruction; and control the first detection branch to output the analog electrical signal parameter on the target LED string to the analog-to-digital converter when the second detection branch samples and holds the analog voltage on other LED strings; The analog electrical signal parameter includes an analog voltage or an analog current.

7. A fault detection method, characterized in that: The fault detection device according to any one of claims 1 to 6 comprises: During the fault detection time period, when any one of the first detection branch and the second detection branch is controlled to sample and hold the analog voltage on the i-th LED string, the other one of the first detection branch and the second detection branch is controlled to sample and hold the analog voltage output on the j-th LED string.

8. An electronic device, characterized in that: It comprises a fault detection device as described in any one of claims 1 to 6.

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