A circuit for preventing high voltage breakdown of consumable chips of printing equipment

Abstract

The present invention provides a circuit for preventing high-voltage breakdown of consumable chips of printing equipment, which can detect all short-circuit faults on the basis of ensuring the normal operation of the chip. The circuit comprises: a comparator, a consumable chip, the consumable chip comprises a short-circuit detection foot, a sensor contact point, and a communication interface respectively connected to a host controller chip for communication; the sensor contact points work in a piezoelectric sensing manner; a GND interface is set in the communication interface, and an equivalent reverse diode is set between each of the remaining communication interfaces and the GND interface; the output end of the comparator is connected to the host controller chip, the positive input end of the comparator is connected to the short-circuit detection foot, and the reverse input end of the comparator is connected to a reference voltage Vref and grounded through resistors R1 and R2 respectively; a diode D1 is set between the GND interface and one of the detection feet in the short-circuit detection foot, the positive electrode of the diode D1 is connected to the GND interface, and one of the detection feet in the short-circuit detection foot is connected to the negative electrode of the diode D1.

Description

Technical Field

[0001] The invention relates to the technical field of consumable chips, and in particular to a circuit for preventing high voltage breakdown of consumable chips of printing equipment. Background Art

[0002] The consumable parts of the printer device, such as ink cartridges, need to interact and communicate with the host (printer controller) during use. Due to the size of the consumable parts, their chips can only be made based on small-sized PCB boards. During the use of the printer device, if ink drops or conductive debris fall on the PCB board, it will cause a short circuit between the ports on the PCB board, thereby damaging the host controller.

[0003] like Figure 1 As shown, it is the PCB board of the consumable chip U1, which includes five communication interfaces C1~C5 for communicating with the host, which provide GND, VDD, and IO (CS, SDL, SDA) for the chip respectively, and there is an electrical connection between the communication interfaces C1~C5; it also includes sensor contact points H1 and H2; short-circuit detection pins S1 and S2; among which, there is a short-circuit connection between H1 and H2, and a short-circuit connection between S1 and S2; the sensor contact points H1 and H2 adopt piezoelectric sensing, so the Hx pin will generate a voltage higher than the Cx pin (for example: Hx=42v, Cx=3.3v).

[0004] Because the size of the previous PCB board was relatively large, the design only considered the problem of always keeping the short circuit between the closest interfaces in one direction, such as Figure 1 In the circuit, between S1 and H1, between S2 and H2; when conductive foreign objects (ink drops, conductive debris) fall on the PCB board, they will connect the nearest contacts that may cause short circuit problems: for example, when S1 and H1 are in contact and short circuit, the short circuit judgment circuit inside the control board determines that a short circuit has occurred, and will turn off the sensor high voltage output to protect the safety of other pins.

[0005] The specific internal short circuit judgment circuit is as follows Figure 2 As shown, in normal working mode, the voltage at S1 terminal is lower than the reference voltage Vref (6.5v), and the output terminal of comparator OP outputs a low level; once two contacts, such as S1 and H1, are in contact and short-circuited, the 42v high voltage of H1 is connected to the S1 terminal, causing the output voltage of comparator OP to change and output a high level; the host controller chip U1 will determine that the chip is short-circuited and stop outputting high voltage, thereby protecting other pins from the impact of high voltage.

[0006] However, as the size of PCB boards gradually decreases, when conductive foreign objects fall on the PCB, they will cover more interfaces at the same time. Figure 3 and Figure 4As shown, the electric contacts Cx and Hx that are far apart may also be connected by a conductive medium, which may also cause a short circuit problem; however, in the pins of the existing consumable chip U1, because the contacts Cx and Hx are not electrically connected, if a conductive foreign object connects Cx and Hx, the existing short circuit judgment circuit cannot detect the occurrence of a short circuit. Summary of the invention

[0007] In order to solve the problem that the existing short-circuit judgment circuit cannot detect all short-circuit faults, the present invention provides a circuit for preventing high-voltage breakdown of consumable chips of printing equipment, which can detect all short-circuit faults on the basis of ensuring the normal operation of the chip.

[0008] The technical solution of the present invention is as follows: a circuit for preventing high-voltage breakdown of consumable chips of printing equipment, comprising: a comparator OP, a consumable chip U1, the consumable chip U1 comprising a short-circuit detection pin, a sensor contact point, and a communication interface respectively connected to a host controller chip U2 for communication; the sensor contact points work in a piezoelectric sensing manner; a GND interface is set in the communication interface, and an equivalent reverse diode is set between each of the remaining communication interfaces and the GND interface; the output end of the comparator OP is connected to the host controller chip U2, an input end of the comparator OP is connected to the short-circuit detection pin, and the other input end of the comparator OP is connected to a reference voltage Vref and grounded through resistors R1 and R2 respectively; it is characterized in that: a forward-biased diode D1 is set between the GND interface and one of the detection pins in the short-circuit detection pin, the positive electrode of the forward-biased diode D1 is connected to the GND interface, and one of the detection pins in the short-circuit detection pin is connected to the negative electrode of the forward-biased diode D1.

[0009] It is further characterized by:

[0010] The short circuit detection pin includes pins S1 and S2, and the pins S1 and S2 are short-circuited; the sensor contact point includes contacts H1 and H2; and the communication interface includes contacts C1 to C5;

[0011] The GND interface is set to contact C4;

[0012] The reference voltage Vref of the comparator OP is 6.5v; the high voltage of the sensor contact point is 42v; and the withstand voltage value of the equivalent reverse diode is 15v.

[0013] The present invention provides a circuit for preventing high-voltage breakdown of consumable chips of printing equipment. A forward-biased diode D1 is arranged between a GND interface of the consumable chip U1 and a short-circuit detection pin. When a sensor contact point and a communication interface are connected by a conductive material, an equivalent reverse diode between the communication interface and the GND interface is broken down, and high voltage is transmitted to S1 through the forward-biased diode D1, so that the output voltage of the comparator OP changes and a high level is output. The host controller chip U1 determines that a short circuit occurs in the chip and stops outputting high voltage, thereby protecting other pins from being impacted by the high voltage. Based on the original short-circuit detection circuit, the forward-biased diode D1 is arranged, which will not affect the normal operation of the chip, but can detect the short-circuit fault between the sensor contact point and the communication interface, ensuring that all short-circuit faults occurring on the chip will be detected, thereby providing a comprehensive protection for the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of the front side of the PCB board of the consumable chip;

[0015] Figure 2 It is a schematic diagram of the structure of an existing short-circuit judgment circuit;

[0016] Figure 3 This is example 1 of a short circuit failure between the sensor contact point and the communication interface;

[0017] Figure 4 Example 2 is a short circuit fault between the sensor contact point and the communication interface;

[0018] Figure 5 The equivalent circuit diagram of the circuit for preventing high voltage breakdown of the patented consumable chip;

[0019] Figure 6 This is an embodiment of a circuit for preventing high voltage breakdown of the consumable chip of the present patent. DETAILED DESCRIPTION

[0020] like Figure 5As shown, the present invention is a circuit for preventing high-voltage breakdown of consumable chips of printing equipment, wherein the consumable chip U1 includes a short-circuit detection pin Sx, a sensor contact point Hx, and a communication interface Cx respectively connected to a host controller chip U2 for communication; the sensor contact point works in a piezoelectric sensing manner; a GND interface is set in the communication interface Cx, and an equivalent reverse diode D2 is set between each of the remaining communication interfaces and the GND interface; the output end of the comparator OP is connected to the host controller chip U2, the forward input end of the comparator OP is connected to the short-circuit detection pin, and the reverse input end of the comparator OP is connected to a reference voltage Vref through a resistor R1 and grounded through a resistor R2; a forward-biased diode D1 is set between the GND interface and one of the detection pins in the short-circuit detection pins, the positive electrode of the forward-biased diode D1 is connected to the GND interface, and one of the detection pins in the short-circuit detection pins is connected to the negative electrode of the forward-biased diode D1.

[0021] like Figure 6 An embodiment is shown, the short circuit detection pin includes pins S1 and S2, and the pins S1 and S2 are short-circuited; the sensor contact point includes contacts H1 and H2; the communication interface includes contacts C1~C5; in this embodiment, the GND interface is set to contact C4; the reference voltage Vref of the comparator OP is 6.5v; the high voltage of the sensor contact point H1 is 42v; the withstand voltage of the equivalent reverse diode is 15v; assuming that there is an electrical short circuit between the contact H1 and C3, but not with S1, due to the characteristics of the integrated circuit and the design of the chip IO, the withstand voltage of the equivalent reverse diode D2 of IO to the ground in the circuit is about 15v; then when H1 and S3 are short-circuited , the voltage at the C3 port will be 42V, which is enough to break down the equivalent reverse diode D2. The GND interface C4 is electrically connected to S1 through the forward-biased diode D1. When the equivalent reverse diode D2 is broken down, the high voltage will be transmitted to S1 through the forward-biased diode D1. In this embodiment, S1 is connected to the positive input terminal of the comparator OP, so that the output voltage at the output terminal of the comparator OP changes and outputs a high level. The host controller chip U1 will determine that a short circuit has occurred in the chip and stop outputting high voltage, thereby protecting the printer controller. In the normal working process, the positive electrode of the forward-biased diode D1 is connected to the GND interface, and the negative electrode is connected to the short-circuit detection pin, which will not affect the operation of the chip's communication interface.

[0022] If the conductive impurities connect the short-circuit detection pin Sx and the communication interface Cx, since these two types of contacts are at low voltage, even if a short circuit occurs, the chip will not be broken down. Only when the short-circuit detection pin Sx, the communication interface Cx and the sensor contact point Hx are short-circuited, the chip will be broken down. Therefore, through the circuit of preventing high-voltage breakdown of this patent, all short-circuit faults between the short-circuit detection pin Sx, the communication interface Cx and the sensor contact point Hx can be detected to protect the safe operation of the equipment.

Claims

1. A circuit for preventing high voltage breakdown of consumable chips of printing equipment, comprising: A comparator OP, a consumable chip U1, wherein the consumable chip U1 includes a short-circuit detection pin, a sensor contact point, and a communication interface respectively connected to the host controller chip U2 for communication; The sensor contact points work in a piezoelectric sensing manner; a GND interface is set in the communication interface, and an equivalent reverse diode is set between each of the other communication interfaces and the GND interface; the output end of the comparator OP is connected to the host controller chip U2, an input end of the comparator OP is connected to the short-circuit detection pin, and the other input end of the comparator OP is connected to the reference voltage Vref and the ground through resistors R1 and R2 respectively; it is characterized in that: a forward-biased diode D1 is set between the GND interface and one of the detection pins in the short-circuit detection pins, the positive electrode of the forward-biased diode D1 is connected to the GND interface, and one of the detection pins in the short-circuit detection pins is connected to the negative electrode of the forward-biased diode D1; The short circuit detection pin includes pins S1 and S2, and the pins S1 and S2 are short-circuited; the sensor contact point includes contacts H1 and H2; the communication interface includes contacts C1 to C5; The reference voltage Vref of the comparator OP is 6.5v; the high voltage of the sensor contact point is 42v; and the withstand voltage value of the equivalent reverse diode is 15v.

2. According to claim 1, a circuit for preventing high voltage breakdown of consumable chips of printing equipment, characterized in that: The GND interface is set to contact C4.

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