Integrated micro heater unit power supply circuit and transistor parallel structure

Abstract

The utility model discloses a micro heater unit power supply circuit and transistor parallel connection structure, which is provided with a first source electrode input port Vs and a first grid electrode input port Vg, and the first source electrode input port Vs is externally connected with a source electrode driving circuit; the first grid input port Vg is externally connected with a grid driving circuit; the utility model provides a simple and practical power supply circuit suitable for the power supply of an integrated micro heater, through the design of connecting a plurality of thin film transistors in parallel, the current to the heater can be increased when a lower voltage is provided, and through the control of the plurality of transistors connected in parallel, the temperature of the heater can be increased. The micro heater can be actually heated in different gradients, the applicability of each heater unit is improved, different heating temperature requirements of different areas in the heater array are met, different temperature requirements in the same heating temperature range can also be met, and the applicability of the heater can be greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of heating devices, in particular to a micro heater unit power supply circuit and a transistor parallel structure. Background Art

[0002] Many electronic devices and equipment have a trend of miniaturization, while the traditional heating method is large in size and complex in structure, which can no longer meet the requirements of miniaturized application scenarios. Therefore, more and more applications require integrated application of microheaters. Microheaters can be used in a variety of scenarios such as gas sensing, smart wearable devices, etc. In existing scenarios, the development of miniaturized, energy-efficient, and integrable microheaters (MEMs microheaters, hereinafter referred to as microheaters) is an effective solution. However, for some application fields that require the use of large-area heater arrays, the integration of multiple microheaters can meet more requirements, such as gas sensors for mixed gas detection and powder sintering. In this case, each heating unit needs to be independently addressed. The best way is to combine the active matrix so that each microheater on the array has a corresponding circuit to realize switch control and power supply. The resistance of the microheater is usually between tens and two hundred ohms, and the temperature required for the application scenario is very wide, usually distributed from room temperature to two hundred degrees Celsius, and sometimes up to 600°C. The size of the heating current passing through the microheater will affect the heating speed and the upper limit temperature. In order to achieve a certain heating speed and upper temperature limit, the heating current is usually above 10mA, while the thin-film transistor, the switching element of the active matrix, can only withstand a limited current.

[0003] Therefore, the problem that needs to be solved when realizing the large-area array integration of microheaters is to develop a power supply circuit that can withstand large currents as a switch control and power supply unit for each pixel in the microheater active matrix. Utility Model Content

[0004] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to provide a heater power supply circuit capable of withstanding a relatively large current, so as to realize switch control and power supply of each heating pixel unit in the micro-heater array.

[0005] Based on the above technical problems, the utility model provides an integrated micro-heater unit power supply circuit, which is provided with a first source input port Vs and a first gate input port Vg, wherein the first source input port Vs is externally connected to a source drive circuit; the first gate input port Vg is externally connected to a gate drive circuit;

[0006] The first gate input port controls the circuit switch through the first thin film transistor T0 to form a connection point A. The second thin film transistor T1 to the N+1th thin film transistor Tn are connected in parallel. After the parallel connection, the gates of the second to the N+1th thin film transistors become a common gate, and the common gate is connected to the connection point A; after the parallel connection, the source electrodes of the second to the N+1th thin film transistors form a common source, and the common source forms a connection point B; after the parallel connection, the drain electrodes of the second to the N+1th thin film transistors form a common drain together, and the common drain is connected to the ground terminal;

[0007] The other end of the connection point B is connected to a constant DC voltage source Vdc through a micro heater R;

[0008] It also includes a capacitor C, one end of which is connected to the connection point A, and the other end of which is grounded.

[0009] The utility model also provides an integrated micro-heater power supply control method, comprising the following steps:

[0010] (1) Arranging a plurality of microheaters to form an array, wherein each microheater is connected to a unit power supply circuit as shown;

[0011] (2) Different heating areas are set according to the gas sensing needs, and the following method is used to control the microheater of each heating area to heat or turn off;

[0012] Using the micro heater power supply circuit as described above, follow the steps below to control and power the heater:

[0013] 1) When the heater needs to be switched from the on state to the off state, control Vg to input a high level and control Vs to input a low level.

[0014] 2) When the heater needs to be switched from the off state to the on state, Vg is controlled to input a high level, and Vs is controlled to input a high level;

[0015] 3) When the heater needs to remain locked in the on state, first follow step 2) to form the on state, and then control Vg to input a low level;

[0016] 4) When the heater needs to remain locked in the off state, first form the off state according to step 1), and then control Vg to input a low level.

[0017] The utility model also provides an integrated micro-heater power supply transistor parallel connection structure, which is applicable to the parallel connection structure of the second thin film transistor T1 to the N+1th thin film transistor Tn of the integrated heater unit power supply circuit, including a source / drain electrode layer, the source / drain electrode layer including a source main body and a drain main body, at least two source branches are arranged on the source main body, at least one drain branch is arranged on the drain main body, the source branch and the drain branch are meshed with each other with a gap, a first gap unit with an edge parallel to the source branch and / or the drain branch, and a second gap unit with an edge parallel to the source main body and / or the drain main body are formed between the source branch and the drain branch; the source main body is externally connected to the micro-heater R;

[0018] A semiconductor layer is disposed on the electrode layer, wherein the semiconductor layer includes at least two semiconductor units, and each of the semiconductor units covers a first gap unit respectively;

[0019] A gate layer is arranged on the electrode layer, and the gate layer includes a gate body. At least two gate branches are arranged on the gate body, and each gate branch covers a corresponding semiconductor unit.

[0020] Preferably, three source branches are arranged on the source main body, three drain branches are arranged on the drain main body, five semiconductor units are arranged on the semiconductor layer, and five gate branches are arranged on the gate main body.

[0021] The beneficial effects of the utility model are as follows: the utility model provides a simple and practical power supply circuit suitable for powering an integrated micro-heater. Through the design of connecting a plurality of thin-film transistors in parallel, a larger current can be input to the micro-heater when a lower voltage is provided, and through the common gate voltage control of the plurality of transistors in parallel, different gradients of heating can actually be achieved for the micro-heater, thereby increasing the applicability of each heater unit, achieving different heating temperature requirements for different areas in the heater array, and achieving different temperature requirements within the same heating temperature range, thereby greatly increasing the applicability of the heater and greatly enhancing its reliability in applicable scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a specific implementation method of the utility model.

[0023] Figure 2 This is a state simulation result diagram of the first embodiment of the utility model during control;

[0024] Figure 3 It is a structural schematic diagram of the third embodiment of the present utility model.

[0025] Figure 4This is a control timing diagram of the fourth embodiment of the present utility model. DETAILED DESCRIPTION

[0026] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0027] Embodiment 1

[0028] like Figure 1 As shown, the utility model provides an embodiment 1 as follows: an integrated micro-heater unit power supply circuit is provided with a first source input port Vs and a first gate input port Vg, the first source input port Vs is externally connected to the source driving circuit; the first gate input port Vg is externally connected to the gate driving circuit; the first gate input port controls the circuit switch through the first thin film transistor T0 to form a connection point A, the second thin film transistor T1 to the N+1th thin film transistor Tn are connected in parallel, and after the parallel connection, the gates of the second to the N+1th thin film transistors become a common gate, and the common gate is connected to the connection point A; after the parallel connection, the sources of the second to the N+1th thin film transistors form a common source, and the common source forms a connection point B; after the parallel connection, the drains of the second to the N+1th thin film transistors jointly form a common drain, and the common drain is connected to the ground; the other end of the connection point B is connected to the constant DC voltage source Vdc through the micro-heater R; and also includes a capacitor C, one end of the capacitor C is connected to the connection point A, and the other end is grounded.

[0029] In this circuit, T0 is a thin film transistor, also known as TFT, which serves as a switch of the circuit. C is a capacitor, which is responsible for maintaining the voltage value of a scanning cycle. T1-Tn are thin film transistors connected in parallel, and the specific number is determined according to actual needs. For example, in Example 2, it is set to 5, and the on resistance of a single TFT is recorded as Ron, and the off resistance is recorded as Roff. The total resistance after n TFTs are connected in parallel is recorded as Ronn (on state) and Roffn (off state). R is a micro heater. The Vdc port is connected to a constant DC voltage source.

[0030] When Vg inputs a high level, T0 turns on and Vs charges capacitor C. If Vs is a high level, the voltage on C also rises to a high level, T1-Tn turns on, and the total parallel resistance decreases. At this time, the partial voltage on R rises, and the current flowing through R also rises. If Vs is a low level, capacitor C discharges, T1-Tn turns off, and the total parallel resistance rises and is much larger than the resistance value of R. At this time, the partial voltage on R is close to 0V, and the current flowing through R can be ignored.

[0031] In this embodiment, reference Figure 2, the heater unit is connected with this circuit to form the simulation result diagram of the on state and the off state. It can be clearly seen that when turned on, the heater part can quickly form a high temperature close to 300 degrees. To achieve this heating temperature, the heating current of the microheater usually needs to be greater than 10mA. If the power supply circuit cannot withstand it, it will cause the performance of the circuit elements to degrade or even break down, and ultimately lead to a decrease in the stability of the array and an increase in the risk.

[0032] By adopting the solution of the utility model, multiple transistors are connected in parallel to quickly achieve higher temperature heating, and by controlling the first source input voltage Vs of different heating units, the heating temperature of each heating unit can be accurately controlled, thereby realizing step temperature control and partitioning of the heater integrated array.

[0033] Embodiment 2

[0034] Embodiment 2. In this embodiment, we perform example calculations on the current and heating power of embodiment 1. Through the calculation process provided in this embodiment and using team data, the effect of embodiment 1 can be verified, and the relevant voltage and current can be monitored in real time.

[0035] During the heating process, the calculation formulas for the current Ion and the heating power P are as follows:

[0036]

[0037] P=I 2 R#(3-2)

[0038] If Vdc=30V, R=200Ω, Ron=20kΩ, n=10, then Ronn=2kΩ, I≈13.6mA.

[0039] When heating is stopped, the calculation formula of the current Ioff is as follows:

[0040]

[0041] If Roff=55GΩ, then Roffn=5.5GΩ, Ioff≈5.5nA, and the total current Ioff after parallel connection can be ignored. Therefore, it can be seen that the first embodiment can actually achieve a better effect.

[0042] Embodiment 3

[0043] In this embodiment, we provide a specific integrated micro-heater power supply transistor parallel structure to illustrate how this patent is implemented. Figure 3The layout design can be specifically carried out in the manner of Example 3. In the figure, the source / drain layer (also called electrode layer) 1, the active layer (semiconductor layer) 2 and the gate layer 3 are arranged in sequence to form an interdigitated electrode structure. This compact structure can ensure that the entire power supply circuit occupies only a very small area relative to the microheater.

[0044] Specifically, the integrated micro-heater power supply transistor parallel structure is suitable for the parallel connection structure of the second thin film transistor T1 to the N+1th thin film transistor Tn of the integrated heater unit power supply circuit of the first and second embodiments. Specifically, the embodiment includes a source / drain electrode layer 1, the source / drain electrode layer 1 includes a source main body 101 and a drain main body 102, at least two source branches 111 are arranged on the source main body 101, and at least one drain branch 122 is arranged on the drain main body 102. The source branch 111 is meshed with the drain branch 122 with a gap, and the source branch 111 is meshed with the drain branch 122. A first gap unit 133 having an edge parallel to the source branch 111 and / or the drain branch 122 and a second gap unit 144 having an edge parallel to the source body 101 and / or the drain body 102 are formed between the branches 122; the source body 101 is externally connected to a micro-heater R; here, when the source body 101 and the drain body 102 are parallel to each other, the second gap unit 144 is parallel to the source body 101 and the drain body 102, and when the source body 101 and the drain body 102 are not parallel, the second gap unit 144 can be parallel to the source body 101 or the drain body 102.

[0045] A semiconductor layer 2 is disposed on the source / drain electrode layer 1, and the semiconductor layer 2 includes at least two semiconductor units, each of which covers a first gap unit 133;

[0046] A gate layer 3 is disposed on the semiconductor layer 2 . The gate layer 3 includes a gate body 301 . At least two gate branches 302 are disposed on the gate body 301 . Each gate branch 302 covers a corresponding semiconductor unit.

[0047] In this embodiment and other embodiments, the heating efficiency of the designed power supply circuit is affected by the resistance wire material (resistivity), resistance wire length, TFT channel material, TFT aspect ratio, etc. of the microheater R. These parameters are factors that need to be considered when adjusting the n value.

[0048] The resistivity and length of the resistance wire have a very direct impact on the heating speed of the micro heater R. Selecting a material with high resistivity, such as ITO, can significantly increase the heating power. From the previous analysis, we can see that R≈0.1Ronn, so R has little effect on Ion, and the heating power is almost proportional to the resistance R. Similarly, extending the length of the resistance wire can also significantly increase the heating power.

[0049] The channel material and aspect ratio of the TFT affect the heating power by affecting the on-current Ion. Selecting a channel material with low on-resistance, such as IGZO, can significantly increase Ion, thereby increasing P. Similarly, increasing the channel aspect ratio can also reduce the on-resistance, thereby achieving the same parallel resistance with fewer parallel TFTs.

[0050] In this embodiment, the parallel TFT can use a common gate when designing the layout of this embodiment, and the source and drain are designed as an interdigitated electrode structure, such as Figure 3 This compact structure ensures that the entire power supply circuit occupies only a small area relative to the micro heater R.

[0051] Embodiment 4

[0052] In this embodiment, we control the control circuit in this patent, demonstrate, and explain the timing diagram of the microheater control in the utility model.

[0053] The specific implementation operation example is as follows: (1) a plurality of micro heaters are arranged to form an array, and each micro heater is connected to the unit power supply circuit of the previous embodiment 1;

[0054] (2) Different heating areas are set according to the gas sensing needs, and the following method is used to control the microheater of each heating area to heat or turn off;

[0055] Using the micro heater power supply circuit described in the previous embodiment, the heater is controlled and powered according to the following steps:

[0056] 1) When the heater needs to be switched from the on state to the off state, control Vg to input a high level and control Vs to input a low level.

[0057] 2) When the heater needs to be switched from the off state to the on state, Vg is controlled to input a high level, and Vs is controlled to input a high level;

[0058] 3) When the heater needs to remain locked in the on state, first follow step 2) to form the on state, and then control Vg to input a low level;

[0059] 4) When the heater needs to remain locked in the off state, first form the off state according to step 1), and then control Vg to input a low level.

[0060] Based on the above rules; see Figure 1 , Vg is the gate input port, which is controlled by the gate driver, Vs is the source input port, which is controlled by the source driver, and a constant voltage is always input to the Vdc terminal. A and B are two key nodes in the circuit.

[0061] During the period t0-t1, Vg inputs a low level, then T0 is turned off, and the original voltage on capacitor C is maintained (here it is assumed that the initial state is a low level). Then node A is a low level, T1-Tn is turned off, and node B outputs a high level, namely Vdc. At this time, the current I passing through R is at the nA level, and it is in a power-off state.

[0062] During the period t1 to t3, Vg inputs a high level, then T0 is turned on, and the voltage on capacitor C is controlled by Vs. During the period t1 to t2, Vs inputs a low level, then C remains at a low level, and VA, VB, and I remain unchanged; during the period t2 to t3, Vs inputs a high level to charge capacitor C, then VA rises to a high level, T1-Tn is turned on, the parallel resistance decreases, the voltage division of R increases, VB drops to the second highest level, and the current passing through R is 10 -2 A level, in heating state.

[0063] During the period from t3 to t8, Vg inputs a low level and T0 is turned off. At this time, no matter how Vs changes, the voltages of each node of the circuit remain unchanged, and the state of the microheater R also remains unchanged.

[0064] During the period of t8 to t10, Vg inputs a high level and T0 is turned on again. At t9, Vs changes from a high level to a low level, and the capacitor C discharges through T0 and also drops to a low level. Then T1-Tn is closed, the parallel resistor is at the GΩ level, and the voltage division of R is almost 0V, returning to the power-off state.

[0065] During the period of t10 to t14, Vg turns to a low level. At this time, the change of Vs will not affect the output. During the period of T14 to t19, the circuit working principle is the same as the above part, which will not be repeated here.

[0066] Through the above power supply circuit, the integrated microheater can be turned on and off with safety, and can generate a large current to achieve rapid heating. In addition, by controlling the input voltage of Vs to control the common gate voltage of the parallel TFT, the current passing through the microheater can be flexibly adjusted, thereby accurately regulating the heating temperature of each heating unit, thereby achieving the temperature gradient and zoned heating of the entire matrix.

[0067] The preferred specific embodiments of the utility model are described in detail above. It should be understood that ordinary technicians in this field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, all technical solutions that can be obtained by technicians in this technical field based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims

1. An integrated micro-heater unit power supply circuit, characterized in that: A first source input port Vs and a first gate input port Vg are provided, wherein the first source input port Vs is externally connected to a source driving circuit; and the first gate input port Vg is externally connected to a gate driving circuit; The first gate input port controls the circuit switch through the first thin film transistor T0 to form a connection point A. The second thin film transistor T1 to the N+1th thin film transistor Tn are connected in parallel. The gates of the second to the N+1th thin film transistors after being connected in parallel become a common gate, and the common gate is connected to the connection point A; the sources of the second to the N+1th thin film transistors after being connected in parallel form a common source, and the common source forms a connection point B; the drains of the second to the N+1th thin film transistors after being connected in parallel form a common drain together, and the common drain is connected to the ground terminal; The other end of the connection point B is connected to a constant DC voltage source Vdc through a micro heater R; It also includes a capacitor C, one end of which is connected to the connection point A, and the other end of which is grounded.

2. An integrated micro-heater unit transistor parallel structure, characterized by: The parallel connection structure of the second thin film transistor T1 to the N+1th thin film transistor Tn suitable for the integrated micro-heater unit power supply circuit as described in claim 1, the parallel connection structure includes a source / drain electrode layer, the source / drain electrode layer includes a source main body and a drain main body, the source main body has at least two source branches, the drain main body is provided with at least one drain branch, the source branch and the drain branch are meshed with a gap, a first gap unit with an edge parallel to the source branch and / or the drain branch, and a second gap unit with an edge parallel to the source main body and / or the drain main body are formed between the source branch and the drain branch; the source main body is externally connected to the micro-heater R; A semiconductor layer is disposed on the electrode layer, wherein the semiconductor layer includes at least two semiconductor units, and each of the semiconductor units covers a first gap unit respectively; A gate layer is arranged on the electrode layer, and the gate layer includes a gate body. At least two gate branches are arranged on the gate body, and each gate branch covers a corresponding semiconductor unit.

3. The integrated micro-heater unit transistor parallel structure as claimed in claim 2, characterized in that: The source electrode body is provided with three source branches, the drain electrode body is provided with three drain branches, the semiconductor layer is provided with five semiconductor units, and the gate electrode body is provided with five gate branches.

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