Time-of-flight distance measuring sensor application system

Abstract

The utility model discloses a flight time distance measuring sensor application system, comprising a DC / DC power supply, a ToF module, an MCU chip and a peripheral circuit, the DC / DC power supply is electrically connected with an input power supply, and the peripheral circuit and the ToF module are both electrically connected with the DC / DC power supply and the MCU chip. The DC / DC power supply is used as the power supply of the time-of-flight (i.e., ToF) distance measuring sensor application system, so that the conversion efficiency of the power supply is improved, and the product energy consumption of the distance measuring application system reaches the corresponding energy consumption standard of the product. Through the DC / DC power supply, the duty ratio or the frequency and the like of the PWM in the DC / DC converter are adjusted, so that the conversion efficiency of the power supply can reach more than 95% at most. Therefore, compared with an LDO (Low Dropout Regulator) power supply, the power supply conversion efficiency can be improved by about 35% through the DC / DC power supply, so that the energy consumption of a flight time distance measuring sensor application system is reduced by about 35%, that is, the use efficiency of a battery is improved by about 35%, and the endurance time of the battery is greatly prolonged.

Description

Technical Field

[0001] The utility model belongs to an application system of a distance measuring sensor, in particular to an application system of a time-of-flight distance measuring sensor. Background Art

[0002] The current time-of-flight (ToF) ranging sensor application systems all use the circuit solution of "LDO (Low Dropout Regulator, low voltage difference linear regulator) power supply + MCU (microcontroller unit) chip + ToF module + peripheral circuit" (such as Figure 1 As shown). The working principle of the time-of-flight ranging module (ToF module): The infrared light emitted by the ToF module is reflected by the obstacle and returns to the receiver of the ToF module. The internal high-speed TDC chip detects the round-trip time difference of this infrared light to determine the distance of the obstacle. Since the time difference detected by the time-of-flight ranging module (ToF module) has nothing to do with the strength and angle of the received signal, it is only related to the distance of the obstacle. Therefore, the time-of-flight ranging module (ToF module) has the characteristics of "anti-chromatic aberration" and "anti-mirror", and is widely used in various ranging scenarios.

[0003] Existing LDO power supplies all use LDO voltage regulator chips as power regulators to provide stable voltage to the time-of-flight ranging module (ToF module), MCU chip and peripheral circuits (circuit block diagram as shown in the figure). Figure 1 The working principle of LDO voltage regulator chip: by adjusting the gate potential of the internal high-power MOS tube, the output voltage can be stabilized. If the voltage at the input end is higher than the voltage at the output end, the excess voltage will be converted into heat in a linear manner, which leads to very low conversion efficiency. The efficiency calculation formula is: η = Vout / Vin×100%.

[0004] The current time-of-flight (ToF) ranging sensor application system, in the application scenario powered by four batteries, such as induction sanitary ware, has an input voltage Vin of up to 6.4V and an output voltage Vout of 3.3V. The LDO power supply in this application system uses an LDO voltage regulator chip as the power regulator, and its efficiency is calculated to be about 52%. Such an LDO power conversion efficiency is very low. Since the working energy consumption of the ToF module itself is generally high, and the low power conversion efficiency of the LDO power supply will greatly reduce the battery efficiency and shorten the battery life. Utility Model Content

[0005] The purpose of the utility model is to provide a time-of-flight ranging sensor application system that can solve the above-mentioned problem.

[0006] According to one aspect of the utility model, a time-of-flight ranging sensor application system is provided, including a DC / DC power supply, a ToF module, an MCU chip and a peripheral circuit, wherein the DC / DC power supply is electrically connected to an input power supply, and the peripheral circuit and the ToF module are both electrically connected to the DC / DC power supply and the MCU chip.

[0007] The beneficial effect of the utility model is that by adopting a DC / DC power supply as the power supply for the time-of-flight (i.e., ToF) ranging sensor application system, the conversion efficiency of the power supply is improved, so that the product energy consumption of the ranging application system reaches the corresponding energy consumption standard of the product. By adjusting the duty cycle or frequency of the PWM inside the DC / DC converter through the DC / DC power supply, the conversion efficiency of the power supply can reach a maximum of more than 95%. Therefore, the power conversion efficiency can be increased by about 35% through the DC / DC power supply, thereby reducing the energy consumption of the time-of-flight ranging sensor application system by about 35%, that is, the battery utilization efficiency is increased by about 35%, which greatly improves the battery life.

[0008] In some embodiments, the DC / DC power supply is a switching power supply, and the DC / DC power supply includes a DC / DC converter, which can convert a DC voltage within a certain range into a required stable DC voltage.

[0009] In some embodiments, the DC / DC power supply is a step-down DC / DC power supply, and thus is suitable for application scenarios where the input voltage is higher than the output operating voltage, and meets corresponding usage requirements.

[0010] In some embodiments, the DC / DC power supply is a boost type DC / DC power supply, and thus is suitable for application scenarios where the input voltage is lower than the output operating voltage, and meets corresponding usage requirements.

[0011] In some embodiments, the DC / DC power supply is a buck-boost DC / DC power supply, which is suitable for application scenarios where the input voltage range is relatively wide, sometimes higher than the output working voltage, and sometimes lower than the output working voltage, meeting corresponding use requirements.

[0012] In some embodiments, the ToF module and the MCU chip are connected via I 2 C bus connection. This facilitates the transmission of MCU chip control signals and facilitates the initialization setting, firmware loading, parameter calibration, starting distance measurement, reading distance data, ending distance measurement, starting sleep and other operations of the ToF module.

[0013] In some implementations, the DC / DC power supply further includes an input capacitor, so that the corresponding noise can be easily filtered out by providing the input capacitor.

[0014] In some embodiments, the DC / DC power supply further includes an output inductor, thereby storing magnetic energy through the output inductor to ensure stable output of current.

[0015] In some embodiments, the DC / DC power supply further includes a voltage divider circuit, and the voltage divider circuit includes a voltage divider resistor. Thus, a voltage divider network is formed through the voltage divider resistor in the voltage divider circuit, and the output voltage is fed back to the control circuit inside the DC / DC converter to accurately control the duty cycle or frequency of the internal PWM and stabilize the output voltage value.

[0016] In some implementations, the DC / DC power supply further includes an output capacitor, thereby facilitating filtering of switch ripples and ensuring a stable and pure output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the circuit principle of a time-of-flight (ToF) ranging sensor application system in the prior art.

[0018] Figure 2 The utility model is a circuit principle diagram of a time-of-flight ranging sensor application system.

[0019] Figure 3 It is a partial circuit diagram of the first embodiment.

[0020] Figure 4 It is a partial circuit diagram of the second embodiment.

[0021] Figure 5 It is a partial circuit diagram of the third embodiment. DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0023] Reference Figure 2 A time-of-flight ranging sensor application system includes a DC / DC power supply, a ToF module, an MCU chip and a peripheral circuit, wherein the DC / DC power supply is electrically connected to an input power supply, and the peripheral circuit and the ToF module are electrically connected to the DC / DC power supply and the MCU chip through wires.

[0024] In actual use, the ToF module integrates the existing VCSEL (Vertical Cavity Surface Emitting Laser), SPAD (Single Photon Avalanche Photodiode) pixel array, time-to-digital converter (TDC) and signal processing circuit in the module to meet the basic requirements of ranging. Among them, VCSEL uses an infrared light source with a wavelength of 700nm to 1100nm that is invisible to the human eye. The ToF module and the MCU chip are connected through I 2C bus connection is used to facilitate the transmission of communication signals. Through the MCU chip, the initialization setting, firmware loading, parameter calibration, starting distance measurement, reading distance data, ending distance measurement, starting sleep and other operations of the ToF module can be controlled. Among them, the control of the ToF module by the MCU chip in the utility model is the same as the control method of the ToF module by the MCU chip in the existing technology, and the specific control process will not be repeated here.

[0025] The MCU chip controls the operation of the entire circuit, and controls the detection cycle and energy consumption of the entire system. While realizing the control of the ToF module, it connects with the peripheral circuits to complete the driving of external action components, the detection of the power supply voltage, the indication of the working status, the protection against power failure, the decoding of the remote control signal, the control of energy consumption, etc. Among them, the control of the peripheral circuit by the MCU chip is the same as the control process of the peripheral circuit by the MCU chip in the prior art.

[0026] The DC / DC power supply is a switching power supply, and the DC / DC power supply includes a DC / DC converter. Therefore, the DC / DC power supply is mainly used to convert the DC voltage within a certain range into the required stable DC voltage. The DC / DC converter in the DC / DC power supply ensures the stable output of the voltage and reduces energy loss by controlling the frequency or duty cycle of the internal PWM of the DC / DC converter according to the input and output voltage conditions. The existing LDO power supply uses an LDO voltage regulator chip as the power regulator, and its power efficiency is as low as 52% (in the application scenario of four batteries powered / output 3.3V). However, using a DC / DC power supply, the power conversion efficiency can be increased by about 35%, thereby reducing the energy consumption of the time of flight (ToF) ranging sensor application system by about 35%, which also increases the battery efficiency by about 35%, greatly improving the battery life.

[0027] Through the high-frequency switching control of the controllable switch (MOSFET, etc.) inside the DC / DC converter, the duty cycle or frequency of the internal PWM is adjusted, and then the energy storage and discharge of the inductor are used to achieve the stability of the output voltage. Due to the characteristics of its switching power supply, the DC / DC converter controls the power supply (DC / DC power supply) and the conversion efficiency can reach more than 95%.

[0028] like Figure 3 As shown, in one embodiment, the DC / DC power supply is a step-down DC / DC power supply. The DC / DC power supply is suitable for application scenarios where the input voltage is higher than the output operating voltage, such as: the input voltage is DC3.6V~10V, and the output voltage is DC2.7V~3.6V.

[0029] like Figure 4As shown, in the second embodiment, the DC / DC power supply is a boost DC / DC power supply. The DC / DC power supply is suitable for application scenarios where the input voltage is lower than the output operating voltage, such as the input voltage is DC0.9V~3.6V and the output voltage is DC2.7V~3.6V.

[0030] like Figure 5 As shown, in the third embodiment, the DC / DC power supply is a buck-boost DC / DC power supply. The DC / DC power supply is suitable for application scenarios where the input voltage range is relatively wide, sometimes higher than the output working voltage, and sometimes lower than the output working voltage, such as the input voltage is DC0.9V~10V and the output voltage is DC2.7V~3.6V.

[0031] The DC / DC power supply also includes input capacitors. When selecting the input capacitor, it is necessary to consider the equivalent inductance and resonant frequency, and select it according to the noise characteristics of different operating frequencies. Large-capacitance capacitors filter low-frequency noise, and small-capacitance capacitors filter high-frequency noise; the combination of large and small-capacitance capacitors in parallel can achieve better filtering effects and stabilize the input voltage. The rated voltage and rated current are the key parameters for selecting input capacitors. The rated voltage is greater than the maximum input voltage. The input capacitor can be an electrolytic capacitor, tantalum capacitor, ceramic capacitor or monolithic capacitor. Specifically, the capacity range of large-capacitance input capacitors is 1~470uF, and the capacity range of small-capacitance input capacitors is 0.01~1uF, which is convenient for the selection of input capacitors.

[0032] The DC / DC power supply also includes an output inductor. Therefore, magnetic energy can be stored through the output inductor to ensure the stable output of current. When selecting the inductance, it is necessary to select the appropriate inductance. A large inductance means small losses, but a slow response. A small inductance means a fast response, but a large loss. Therefore, in actual use, it is necessary to find a balance between efficiency and response speed and select an output inductor with a suitable inductance; at the same time, consider the saturation current to ensure the filtering effect. The inductance ranges from 0.1μH to 100μH, and its DC resistance is less than 1000mΩ.

[0033] The DC / DC power supply also includes a voltage divider circuit, which includes a voltage divider resistor. Therefore, a voltage divider network is formed through the voltage divider resistor, and the output voltage is fed back to the control circuit inside the DC / DC converter to accurately control its PWM duty cycle or frequency and stabilize the output voltage value. High-precision resistors are selected to enable accurate, stable and fast feedback of the output voltage to ensure the accuracy of the output voltage. The output voltage value is determined by the resistance ratio of the voltage divider network. Specifically, the output voltage value V OUT =K(1+R1 / R2) (K is a constant, K=0.3~2), the resistance values ​​of R1 and R2 should be greater than 0.2MΩ to reduce standby power consumption.

[0034] The DC / DC power supply also includes output capacitors. Among them, the output capacitor needs to comprehensively consider the capacitance and ESR to minimize ripple, filter out switching ripple, and ensure the stability and purity of the output voltage. The larger the capacitance, the smaller the impedance and the smaller the ripple; the capacity range of large-capacitance output capacitors: 1~470uF, and the capacity range of small-capacitance output capacitors: 0.01~1uF. In actual use, you can choose a suitable output capacitor according to specific usage requirements to meet different usage requirements.

[0035] In summary, the utility model discloses a time-of-flight ranging sensor application system, which adopts a DC / DC power supply and controls the frequency or duty cycle of the internal PWM of the DC / DC converter according to the input and output voltage conditions, to ensure stable voltage output, improve power supply efficiency, and reduce the power consumption of the time-of-flight (ToF) ranging sensor application system.

[0036] The above are only preferred implementations of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A time-of-flight ranging sensor application system, characterized in that: It includes a DC / DC power supply, a ToF module, an MCU chip and a peripheral circuit. The DC / DC power supply is electrically connected to an input power supply, and the peripheral circuit and the ToF module are both electrically connected to the DC / DC power supply and the MCU chip.

2. A time-of-flight ranging sensor application system according to claim 1, characterized in that: The DC / DC power supply is a switching power supply, and the DC / DC power supply includes a DC / DC converter.

3. A time-of-flight ranging sensor application system according to claim 2, characterized in that: The DC / DC power supply may be a step-down DC / DC power supply.

4. A time-of-flight ranging sensor application system according to claim 2, characterized in that: The DC / DC power supply may be a boost type DC / DC power supply.

5. A time-of-flight ranging sensor application system according to claim 2, characterized in that: The DC / DC power supply may be a buck-boost DC / DC power supply.

6. A time-of-flight ranging sensor application system according to any one of claims 1 to 5, characterized in that: The ToF module and the MCU chip are connected via I 2 C-bus connection.

7. A time-of-flight ranging sensor application system according to any one of claims 3 to 5, characterized in that: The DC / DC power supply also includes an input capacitor.

8. A time-of-flight ranging sensor application system according to claim 7, characterized in that: The DC / DC power supply further includes an output inductor.

9. A time-of-flight ranging sensor application system according to claim 8, characterized in that: The DC / DC power supply further includes a voltage dividing circuit, and the voltage dividing circuit includes a voltage dividing resistor.

10. A time-of-flight ranging sensor application system according to claim 9, characterized in that: The DC / DC power supply also includes an output capacitor.

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