WO2022057219A1

WO2022057219A1 - High voltage breakdown prevention circuit for printing device consumable chip

Info

Publication number: WO2022057219A1
Application number: PCT/CN2021/079952
Authority: WO
Inventors: 陈钟鹏; 余自然; 吴梦钰; 张帅
Original assignee: 无锡翼盟电子科技有限公司
Priority date: 2020-09-18
Filing date: 2021-03-10
Publication date: 2022-03-24
Also published as: CN112067976A

Abstract

A high voltage breakdown prevention circuit for a printing device consumable chip which is capable of detecting all short circuit faults while ensuring the normal operation of the consumable chip (U1). The circuit comprises a comparator (OP) and a consumable chip (U1). The consumable chip (U1) comprises short circuit detection pins (Sx), sensor contact points (Hx) and communication interfaces (Cx) which have separate communicative connections with a host controller (U2). Piezoelectric sensing is used in the work between sensor contact points (Hx). A GND interface is arranged in a communication interface (Cx), and an equivalent reverse diode (D2) is arranged between each of the remaining communication interfaces (Cx) and the GND interface. The output end of the comparator (OP) is connected to the host controller chip (U2), the positive input end of the comparator (OP) is connected to the short circuit detection pins (Sx), and the reverse input end of the comparator (OP) is connected to the reference voltage (Vref) and the ground respectively by means of resistors R1 and R2. A diode (D1) is arranged between the GND interface and one of the short circuit detection pins (Sx). The positive electrode of the diode (D1) is connected to the GND interface, and one of the short circuit detection pins (Sx) is connected to the negative electrode of the diode (D1).

Description

A circuit used for printing equipment consumables chip to prevent high voltage breakdown

technical field

The invention relates to the technical field of consumable chips, in particular to a circuit for preventing high-voltage breakdown of a consumable chip of a printing equipment.

Background technique

Consumable parts of printer equipment, such as ink cartridges, need to communicate with the host (printer controller) during use; limited by the size of consumable parts, their chips can only be made based on small-sized PCB boards; during the use of printer equipment, If ink droplets or conductive debris fall on the PCB board, it will cause a short circuit between the ports on the PCB board, thereby causing damage to the host controller; as shown in Figure 1, it is the PCB board of the consumable chip U1, which includes five The communication interfaces C1~C5 that communicate with the host provide GND, VDD, and IO (CS, SDL, SDA) for the chip respectively. There is an electrical connection between the communication interfaces C1~C5; it also includes the sensor contact point H1 , H2; short-circuit detection pins S1, S2; among them, the short-circuit connection between H1 and H2, and the short-circuit connection between S1 and S2; the sensor contact points H1, H2 use piezoelectric sensing, so the Hx pin will generate higher than The voltage of the Cx pin (for example: Hx=42v, Cx=3.3v).

technical problem

Because the size of the previous PCB board is relatively large, only the short-circuit problem between the closest interfaces in one direction is always considered in the design, as shown in Figure 1, between S1 and H1, between S2 and H2; when conductive Foreign objects (ink droplets, conductive fragments) falling on the PCB will turn on the nearest contacts that will cause short-circuit problems: for example, when S1 and H1 are short-circuited, the short-circuit judgment circuit inside the control board judges that a short-circuit has occurred. The high voltage output of the sensor will be turned off to protect the safety of other pins.

The specific internal short-circuit judgment circuit is shown in Figure 2. In the normal working mode, the voltage of the S1 terminal is lower than the reference voltage Vref (6.5v), and the output terminal of the comparator OP outputs a low level at this time; For example: when S1 and H1 are short-circuited, the 42v high voltage of H1 is connected to the S1 terminal, so that the output voltage of the comparator OP changes and outputs a high level; the host controller chip U1 will judge that the chip is short-circuited, and stop outputting high voltage, So as to protect other pins from the impact of high voltage.

However, as the size of the PCB becomes smaller, when the conductive foreign object falls on the PCB, it will cover more interfaces at the same time. As shown in Figure 3 and Figure 4, the electric shock Cx and Hx are far apart There is also the possibility of being connected by a conductive medium, which will 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, so if the conductive When the foreign object connects Cx and Hx, the existing short circuit judgment circuit cannot detect the occurrence of the short circuit.

technical solutions

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

The technical solution of the present invention is as follows: a circuit for preventing high-voltage breakdown of a consumable chip of a printing equipment, which includes: a comparator OP, a consumable chip U1, and the consumable chip U1 includes short circuits respectively connected to the host controller chip U2 in communication Detection feet, sensor contact points, and communication interfaces; piezoelectric sensing is used between the sensor contact points; a GND interface is set among the communication interfaces, and each of the other communication interfaces is respectively connected to the GND An equivalent reverse diode is set between the interfaces; 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 The other input terminal is respectively connected to the reference voltage Vref and ground through the resistors R1 and R2; it is characterized in that: a diode D1 is set between the GND interface and one of the short-circuit detection pins, and the diode D1 is The positive pole is connected to the GND interface, and one of the short-circuit detection pins is connected to the negative pole of the diode D1.

It is further characterized in that: the short-circuit detection pins include pins S1 and S2, and the pins S1 and S2 are short-circuited; the sensor contact points include contacts H1 and H2; the communication interface includes contacts C1 to C5; The GND interface is set as the contact C4; the reference voltage Vref of the comparator OP is 6.5v; the high voltage of the sensor contact point is 42v; the withstand voltage of the equivalent reverse diode is 15v.

beneficial effect

The present invention provides a circuit for preventing high-voltage breakdown of consumable chips for printing equipment. By setting a forward-biased diode D1 between the GND interface of the consumable chip U1 and the short-circuit detection pin, when the contact point of the sensor and the communication interface are electrically conductive After the substance is turned on, after the equivalent reverse diode between the communication interface and the GND interface is broken down, the high voltage is transmitted to S1 through the forward biased diode D1, so that the output voltage of the comparator OP changes and outputs a high level, and the host controller The chip U1 will judge that the chip is short-circuited and stop outputting high voltage, thereby protecting other pins from the impact of high voltage; on the basis of the original short-circuit detection circuit, the setting of the forward-biased diode D1 will not affect the normal operation of the chip. However, the short-circuit fault between the sensor contact point and the communication interface can be detected to ensure that the short-circuit fault that occurs on the chip will be detected, and the chip will be fully protected.

Description of drawings

Fig. 1 is the structural schematic diagram of the front side of the PCB board of the consumables chip; Fig. 2 is the existing short circuit judgment circuit structure schematic diagram; Example 2 of a short-circuit fault at the interface; Figure 5 is an equivalent circuit diagram of the patented consumable chip preventing high-voltage breakdown circuit; Figure 6 is an embodiment of the patented consumables chip's circuit for preventing high-voltage breakdown.

Embodiments of the present invention

As shown in FIG. 5, the present invention is a circuit for preventing high-voltage breakdown of a consumable chip of a printing equipment. The consumable chip U1 includes a short-circuit detection pin Sx, a sensor contact point Hx, and a communication interface Cx that are respectively connected to the host controller chip U2 in communication; the sensor; The contact point works by piezoelectric sensing; a GND interface is set in the communication interface Cx, and an equivalent reverse diode D2 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, the forward input terminal of the comparator OP is connected to the short-circuit detection pin, the reverse input terminal of the comparator OP is connected to the reference voltage Vref through the resistor R1, and is grounded through the resistor R2; between the GND interface and the short-circuit detection pin A diode D1 is set between one detection pin, the anode of the diode D1 is connected to the GND interface, and one of the short-circuit detection pins is connected to the cathode of the diode D1.

As shown in FIG. 6, an embodiment is shown. The short-circuit detection pins include pins S1 and S2, and the pins S1 and S2 are short-circuited; the sensor contact points include contacts H1 and H2; the communication interface includes contacts C1 to C5; this embodiment The middle 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; it is assumed that there is an electrical short circuit between the chip H1 and C3 , without short-circuiting with S1, due to the characteristics of integrated circuits and the design of chip IO, the withstand voltage of the equivalent reverse diode D2 of IO to ground in the circuit is about 15v; then when H1 and S3 are short-circuited , the C3 port voltage 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 diode D2 is broken down, the high voltage will pass through the forward-biased diode D1. It is transmitted to S1. In this embodiment, S1 is connected to the positive input terminal of the comparator OP, so that the output voltage of the output terminal of the comparator OP changes and outputs a high level. The host controller chip U1 will judge that the chip is short-circuited and stop outputting high voltage. , to protect the printer controller; during normal operation, the positive pole of the forward bias diode D1 is connected to the GND interface, and the negative pole is connected to the short-circuit detection pin, which will not affect the work of the chip's communication interface.

If the conductive impurities are connected to the short-circuit detection pin Sx and the communication interface Cx, because these two types of contacts are low voltage, even if a short circuit occurs, there will be no breakdown of the chip; only the short-circuit detection pin Sx and the communication interface Cx When the contact point Hx with the sensor is short-circuited, the problem of chip breakdown occurs. Therefore, through the circuit for preventing high-voltage breakdown in this patent, all short-circuit detection pins Sx, communication interface Cx and sensor contact point Hx can be detected. short-circuit fault between, to protect the safe operation of the equipment.

Claims

A circuit for preventing high-voltage breakdown of a consumable chip of a printing equipment, which includes: a comparator OP, a consumable chip U1, and the consumable chip U1 includes a short-circuit detection pin, a sensor contact point, and a communication interface respectively communicatively connected to a host controller chip U2 ; The sensor contact points work in a piezoelectric sensing mode; a GND interface is set in the communication interface, and an equivalent reverse is set between each of the remaining communication interfaces and the GND interface respectively diode; the output end of the comparator OP is connected to the host controller chip U2, one 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 resistor R1, R2 is connected to the reference voltage Vref and ground; it is characterized in that: a diode D1 is set between the GND interfaces and one of the short-circuit detection pins, and the anode of the diode D1 is connected to the GND interface, and the One of the short-circuit detection pins is connected to the cathode of the diode D1.
The circuit for preventing high-voltage breakdown of a consumable chip of a printing equipment according to claim 1, wherein the short-circuit detection pin comprises pins S1 and S2, and the pins S1 and S2 are short-circuited; the sensor contacts The points include contacts H1, H2, and the communication interface includes contacts C1-C5.
The circuit for preventing high-voltage breakdown of a consumable chip for printing equipment according to claim 2, wherein the GND interface is set as a contact C4.
The circuit for preventing high-voltage breakdown of a consumable chip for printing equipment according to claim 1, characterized in that: the reference voltage Vref of the comparator OP is 6.5v; the high-voltage of the contact point of the sensor is 42v; the etc. The withstand voltage of the effective reverse diode is 15v.