Smoke sensing chip low-power-consumption system based on two buses

Abstract

The invention discloses a smoke sensing chip low-power-consumption system based on two buses. The smoke sensing chip low-power-consumption system comprises a two-bus power data receiving and transmitting module. The two-bus power data transceiver module comprises three D / A converters, a completely integrated operational amplifier and two comparators, integrates voltage code receiving, current code returning and automatic discharging functions, and is used for detecting voltage and current signals on two buses to dynamically adjust the working state of the communication module; the normally open core module only keeps a low-power-consumption timer for maintaining a time reference and triggering a periodic task; an on-demand wake-up module; and the on-demand awakening module is used for being interrupted and awakened by a timer, only executing necessary tasks after awakening, including smoke detection and data processing, and immediately returning to sleep after the tasks are completed. The two buses can be used for receiving and sending data, and only serve as a power line to provide stable power supply when communication is not carried out; the communication stage is only temporarily activated and is in a dormant state in other time, so that the overall power consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of smoke sensor chip technology, specifically to a low-power smoke sensor chip system based on a two-bus architecture. Background Technology

[0002] Smoke detectors are the core devices for early fire detection, with the smoke sensor chip at their core responsible for smoke signal detection, data processing, and communication reporting. Traditional smoke sensor chips typically employ an architecture of independent power supply (such as a battery) + multi-line communication (such as separate power lines, ground lines, and communication lines), which has the following prominent problems: High power consumption: Multi-line communication requires continuous maintenance of the communication line's driving state (such as level maintenance and signal handshake), and the internal modules of the chip (such as communication circuits and detection circuits) are often in a high-power operation mode, resulting in short battery life (usually requiring replacement every 1-3 years) and high maintenance costs; Poor two-bus compatibility: Existing two-bus systems (such as RS-485 variants and HART protocols in the fire protection field) are mostly used in industrial instruments, and their communication protocols are complex (requiring handshake, verification, and address allocation). Smoke detector chips need to integrate additional protocol processing modules to adapt to two-bus systems, further increasing power consumption and cost; In addition, the chip needs to continuously monitor the bus signal during traditional two-bus communication and cannot enter deep sleep mode; Limitations of low-power design: Existing low-power solutions mostly detect smoke by intermittent wake-up (such as waking up once per second), but the communication module still remains in standby mode, resulting in limited overall power consumption optimization and making it difficult to meet the market demand for "10-year long-lasting batteries". Summary of the Invention

[0003] The purpose of this invention is to provide a low-power smoke detector chip system based on a two-bus architecture to solve the problems mentioned in the background art.

[0004] This invention discloses a low-power system for a smoke detector chip based on a two-bus architecture, including a two-bus power data transceiver module. The two-bus power data transceiver module consists of three D / A converters, a fully integrated operational amplifier, and two comparators, and integrates voltage code reception, current code return, and automatic discharge functions to detect voltage and current signals on the two-bus and dynamically adjust the working state of the communication module. A normally open core module; the normally open core module only maintains a low-power timer to maintain the time base and trigger periodic tasks; an on-demand wake-up module; the on-demand wake-up module is used to be woken up by a timer interrupt, and after waking up, it only performs necessary tasks, including smoke detection and data processing, and immediately returns to sleep mode after the tasks are completed; Edge detection module; the edge detection module monitors the edge changes of the bus signal in real time, including rising and falling edges; when an edge is detected, it outputs an edge trigger signal, and generates a trigger pulse for each valid edge detected; The counting module has two built-in counters, EDGCNT and CAP_TIMER. EDGCNT is used to count edge-triggered signals, and CAP_TIMER is used to count pulse widths. Upon receiving a full count signal from EDGCNT or an overflow signal from CAP_TIMER, an interrupt signal is generated. CPU module; The CPU module is used to wake up from sleep state after receiving an interrupt signal, decode the instruction sequence sent by the bus, execute the corresponding task, and then re-enter sleep state to wait for the next interrupt.

[0005] The present invention is further configured such that: the dual-bus power data transceiver module integrates a bus signal detection circuit, which activates the communication processing module only when a valid data frame start signal is detected on the dual-bus; when there is no communication, the communication processing module is in a completely off state.

[0006] The present invention is further configured such that: the dual-bus power data transceiver module is only briefly activated during the communication phase, completes data interaction in 1-2ms, and remains in a sleep state for the rest of the time, while the communication processing module is in a closed state.

[0007] The present invention is further configured such that: when the counting template is counting, a "wake-up threshold N" is preset and reasonably set according to the bus protocol. When the edge counter counts to N, a full count signal is output; if the CAP_TIMER does not detect a new edge before the count reaches N, the counter is automatically cleared to zero and waits for the edge to trigger again.

[0008] A method for using a low-power smoke detector chip based on a two-bus architecture includes the following steps: Step 1: By default, the MCU, detection module, and communication module are all in sleep mode. When a valid data frame start signal is detected on the two buses, for example, when a certain voltage appears on the comparator bus voltage, an edge interrupt is generated to wake up the MCU, or the MCU is woken up by a timer. After waking up, the smoke detection module performs smoke detection. If the smoke exceeds the standard, the alarm data is uploaded through the communication module. Then all modules return to sleep mode. Step 2: After power-on, initialize the chip, start the timer, and enter sleep mode. The timer duration is the delay between two frames of data during host polling. After the timer ends, wake up the CPU, start smoke detection, compare the detected value with the set threshold to determine if there is smoke, and check if the ID sent by the host is its own ID. If it is not its own ID, return to restart the timer and enter sleep mode, waiting for the next wake-up. If its own ID is detected, report the presence or absence of smoke signal, and then return to restart the timer and enter sleep mode, waiting for the next wake-up.

[0009] The present invention is further configured as follows: after power-on in step two, the chip is initialized, enters sleep mode, waits for a valid data frame start signal to appear on the two buses, and is woken up by a comparator edge interrupt; after waking up, it first compares whether it is 8V. If not, it returns to sleep mode and continues to wait; if it is, it enables smoke detection, compares the detected value with a set threshold to determine whether there is smoke; it checks whether the ID sent by the host is its own ID. If it is not its own ID, it returns to sleep mode and waits for the next wake-up; if its own ID is detected, it reports a smoke or no smoke signal, and then returns to sleep mode and waits for the next wake-up.

[0010] The invention is further configured as follows: In order to reduce the overall power consumption, the CPU can enter a sleep state while communicating with the host. The CPU is woken up by an edge interrupt of the CAP module to handle related events. After configuring the relevant registers of the CAP capture function, the CPU enters green mode 1. The CAP module can still work. After executing SLEEP in this mode, the internal high frequency, external low frequency, internal low frequency and system clock are all on, and the instruction clock is off. Alternatively, the CPU can enter a sleep mode. The clock of each functional module uses the RC400K clock. After detecting an edge trigger, the internal counter starts working and compares the corresponding edge. After completing the communication with the host, the CPU enters a sleep state and waits for a new round of smoke detection. During this stage, the CPU is only in working state when processing the interrupt service routine. At other times, the CPU is in a sleep state.

[0011] The present invention is further configured as follows: The MCU first writes a comparison value into the CAPEDGC register to set the number N of sampling edges; writes two comparison values into CAPCOMP0 and CAPCOMP1 for comparing the widths M0 / M1 of the levels; when the starting edge of the bus code voltage occurs, the counter CAP_TIMER starts to count. When an edge is detected, the count value of CAP_TIMER is compared with CAPCOMP0 and CAPCOMP1, and the comparison result is stored in the shift register SBUF. If CAP_TIMER > CAPCOMP0, 1 is stored in SBUF. When CAPCOMP1 < CAP_TIMER < CAPCOMP0, 0 is stored in SBUF; at the same time, the edge counter EDGCNT is incremented by 1. When EDGCNT = CAPEDGC, an interrupt is generated to wake up the CPU. The value in the shift register SBUF is read out for decoding. After the decoding is completed, it immediately returns to the sleep state and waits for the next interrupt; writes a comparison value into TMIEROV. When the edge counter EDGCNT does not reach N and CAP_TIMER does not detect a new edge after exceeding the preset time TMIEROV, the counters EDGCNT and CAP_TIMER are automatically cleared, the CPU is woken up, the value in the shift register SBUF is read out for decoding, and the software determines whether all sequences have been decoded. After all tasks are completed, it immediately returns to the sleep state again and waits for the edge trigger.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: The low-power system of the smoke sensor chip based on the two-wire bus 1. It solves the problem that multi-wire communication needs to continuously maintain the driving state of the communication line, and the internal modules of the chip are often in the running mode, resulting in high power consumption; the two-wire bus can be used for data reception and transmission. When not communicating, it only serves as a power supply line to provide a stable power supply; it is only briefly activated during the communication stage and is in the sleep state for the rest of the time, reducing the overall power consumption.

[0013] 2. It solves the problem that the existing low-power solutions mostly detect smoke through intermittent wake-up, but the communication module still remains in the standby state, and the overall power consumption optimization is limited; by waking up each module at different times, at the same time, the communication module adopts the method of sampling multiple edges to wake up during the communication process. The CPU is only woken up after detecting multiple edges, and only executes necessary tasks after waking up. After the tasks are completed, it immediately returns to the sleep state and is in the sleep state for most of the time, significantly reducing the standby power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic flowchart of the present invention for waking up the CPU regularly; Figure 2 is a schematic flowchart of the present invention for waking up the CPU by edge interrupt; Figure 3This is a schematic diagram illustrating the timing of sampling multiple edge interrupts to wake up the CPU in this invention; Figure 4 This is a system block diagram of the two-bus smoke sensor chip based on a photoelectric smoke sensor according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] This invention provides a technical solution: a low-power smoke detector chip system based on a two-bus bus, including a two-bus power data transceiver module; the two-bus power data transceiver module consists of three D / A converters, a fully integrated operational amplifier and two comparators, and integrates voltage code reception, current code return and automatic discharge functions, used to detect the voltage and current signals on the two-bus bus to dynamically adjust the working state of the communication module; Normally open core module; The normally open core module only maintains a low-power timer to maintain the time base and trigger periodic tasks; On-demand wake-up module; The on-demand wake-up module is used to be woken up by a timer interrupt. After waking up, it only performs necessary tasks, including smoke detection and data processing. After the tasks are completed, it immediately returns to sleep mode. Edge detection module; The edge detection module monitors the edge changes of the bus signal in real time, including rising and falling edges; When an edge is detected, it outputs an edge trigger signal, and generates a trigger pulse for each valid edge detected; The counting module has two built-in counters, EDGCNT and CAP_TIMER. EDGCNT is used to count edge-triggered signals, and CAP_TIMER is used to count pulse widths. An interrupt signal is generated upon receiving a full count signal from EDGCNT or an overflow signal from CAP_TIMER. CPU module: The CPU module is used to wake up from sleep mode after receiving an interrupt signal, decode the instruction sequence sent by the bus, execute the corresponding task, and then re-enter sleep mode to wait for the next interrupt.

[0017] The dual-bus power data transceiver module integrates a bus signal detection circuit, which activates the communication processing module only when a valid data frame start signal is detected on the dual-bus. When there is no communication, the communication processing module is completely off. The dual-bus power data transceiver module is only briefly activated during the communication phase, completing data exchange in 1-2ms, and remains in sleep mode for the rest of the time, while the communication processing module is off. The counting template first presets a "wake-up threshold N" during counting, which is reasonably set according to the bus protocol. When the edge counter reaches N, it outputs a full count signal. If CAP_TIMER does not detect a new edge before the count reaches N, the counter is automatically reset to zero and waits for an edge trigger again.

[0018] Example 1 Reference Figure 1 A method for using a low-power smoke detector chip based on a two-bus architecture includes the following steps: Step 1: By default, the MCU, detection module, and communication module are all in sleep mode. When a valid data frame start signal is detected on the two buses, for example, when a certain voltage appears on the comparator bus voltage, an edge interrupt is generated to wake up the MCU, or the MCU is woken up by a timer. After waking up, the smoke detection module performs smoke detection. If the smoke exceeds the standard, the alarm data is uploaded through the communication module. Then all modules return to sleep mode. Step 2: After power-on, initialize the chip, start the timer, and enter sleep mode. The timer duration is the delay between two frames of data during host polling. After the timer ends, wake up the CPU, start smoke detection, compare the detected value with the set threshold to determine if there is smoke, and check if the ID sent by the host is its own ID. If it is not its own ID, return to restart the timer and enter sleep mode, waiting for the next wake-up. If its own ID is detected, report the presence or absence of smoke signal, and then return to restart the timer and enter sleep mode, waiting for the next wake-up.

[0019] Example 2 Reference Figure 2 A method for using a low-power smoke detector chip based on a two-bus architecture includes the following steps: Step 1: By default, the MCU, detection module, and communication module are all in sleep mode. When a valid data frame start signal is detected on the two buses, for example, when a certain voltage appears on the comparator bus voltage, an edge interrupt is generated to wake up the MCU, or the MCU is woken up by a timer. After waking up, the smoke detection module performs smoke detection. If the smoke exceeds the standard, the alarm data is uploaded through the communication module. Then all modules return to sleep mode. Step 2: After power-on, the chip is initialized and enters sleep mode, waiting for a valid data frame start signal on the second bus. The CPU is woken up by a comparator edge interrupt. After waking up, the CPU first compares whether the voltage is 8V. If not, it returns to sleep mode and continues to wait. If the voltage is 8V, smoke detection is enabled. The detected value is compared with a set threshold to determine if there is smoke. The CPU checks whether the ID sent by the host is its own ID. If it is not its own ID, it returns to sleep mode and waits for the next wake-up. If its own ID is detected, it reports a smoke or no-smoke signal and then returns to sleep mode, waiting for the next wake-up.

[0020] In the above embodiments, reference is made to Figure 3 To further reduce overall power consumption, the CPU can enter a sleep state while communicating with the host. It can be woken up by an edge interrupt from the CAP module to handle related events. After configuring the relevant registers for the CAP capture function, it enters green mode 1. The CAP module can still work. In this mode, after executing SLEEP, the internal high frequency, external low frequency, internal low frequency, and system clock are all on, while the instruction clock is off. Alternatively, it can enter sleep mode. The clock for each functional module is RC400K. After detecting an edge trigger, the internal counter starts working and compares the corresponding edge. After completing communication with the host, it enters sleep mode and waits for a new round of smoke detection. During this stage, the CPU is only in working state when processing the interrupt service routine; otherwise, it is in sleep mode. Further, the MCU first writes a comparison value into the CAPEDGC register to set the number N of sampling edges; writes two comparison values into CAPCOMP0 and CAPCOMP1 for comparing the widths M0 / M1 of the levels. After the start edge of the bus coding voltage, the counter CAP_TIMER starts counting. When an edge is detected, the count value of CAP_TIMER is compared with CAPCOMP0 and CAPCOMP1, and the comparison result is stored in the shift register SBUF. If CAP_TIMER > CAPCOMP0, 1 is stored in SBUF; when CAPCOMP1 < CAP_TIMER < CAPCOMP0, 0 is stored in SBUF. At the same time, the edge counter EDGCNT is incremented by 1. When EDGCNT = CAPEDGC, an interrupt is generated to wake up the CPU. The value in the shift register SBUF is read out for decoding. After decoding is completed, it immediately returns to sleep and waits for the next interrupt. A comparison value is written into TMIEROV. When the edge counter EDGCNT does not reach N and CAP_TIMER does not detect a new edge after exceeding the preset time TMIEROV, the counters EDGCNT and CAP_TIMER are automatically cleared, the CPU is awakened, the value in the shift register SBUF is read out for decoding, and the software determines whether all sequences have been decoded. After all tasks are executed, it immediately returns to sleep again and waits for an edge trigger.

[0021] Referring to Figure 4 , in order to verify the above technical solution, a two-wire smoke detector chip based on a photoelectric smoke sensor is designed based on the above solution; 1. Hardware Design Smoke detector AFE: Used to detect whether there is smoke. When there is smoke, the current of the receiver will increase. It is given to the ADC through the two-stage operational amplifier of the AFE. After the ADC samples, it is given to the digital part. Whether there is smoke is detected by software judging whether the sampled value is greater than the set threshold.

[0022] Power line transceiver PLT: This module includes a code receiving, code returning, and automatic discharge module.

[0023] Code receiving: The bus voltage enters the comparator through PLRX and is compared with the set voltage to generate a level signal given to the digital part. The CAP capture module decodes the received level signal to obtain ID information, etc.; Code returning: After judging whether there is smoke, the digital part controls the code returning switch part, and the information is returned to the host through PLTX. The host decodes the bus waveform to judge whether there is a smoke alarm; Automatic discharge module: Enabling the automatic discharge can improve the distortion of the two-wire communication waveform and enhance the stability MCU: Controls the coordinated operation of each module; 2. Software Logic Step 1: Initialization: After power-on, initialize each module; Step 2: Enable CMP0 / CMP1, and set CMP0 to wake up the CPU via a falling edge interrupt (assuming the host uses three communication levels). After setting, enter sleep mode. Step 3: When a valid data frame start signal is detected on the second bus (e.g., 24V drops to 8V), the CMP0 falling edge interrupt wakes up the CPU; Step 4: After waking up, turn on the smoke detector AFE and ADC module to start smoke detection; Step 5: After the smoke detection is completed, the CAP module is turned on. The information sent by the bus is decoded by sampling multiple edges to generate interrupts. It is determined whether it is its own ID. If it is not its own ID, it returns to step 2; if it is its own ID, it proceeds to step 6. Step 6: By controlling the feedback circuit, send a reply to the host indicating whether there is smoke or not; Return to step 2 and begin a new round of testing.

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A low power consumption system based on two-bus smoke sensing chip, characterized in that, The two-bus power data transceiver module includes three D / A converters, a fully integrated operational amplifier and two comparators, integrated voltage receiving code, current returning code and automatic discharge function, and is used for detecting voltage and current signals on the two bus and dynamically adjusting the working state of the communication module. The always-on core module only maintains a low-power timer for maintaining a time reference and triggering periodic tasks; the on-demand wakeup module is used to wake up by a timer interrupt, and after waking up, only necessary tasks including smoke detection and data processing are performed, and the module returns to sleep immediately after completing the tasks. The edge detection module monitors the edge changes of the bus signals in real time, including rising edge and falling edge; when an edge is detected, an edge trigger signal is output, and a trigger pulse is generated for each valid edge detected. The counting module has two counters, EDGCNT and CAP_TIMER, EDGCNT is used for counting the edge trigger signal, and CAP_TIMER is used for counting the pulse width; after receiving the EDGCNT full count signal or the CAP_TIMER overflow signal, an interrupt signal is generated. The CPU module is used for waking up from the sleep state after receiving the interrupt signal, decoding the instruction sequence sent by the bus, and re-entering the sleep state after completing the corresponding tasks, and waiting for the next interrupt.

2. The low power system based on two-bus smoke sensing chip according to claim 1, characterized in that, The two-bus power data transceiver module integrates a bus signal detection circuit, and only activates the communication processing module when valid data frame start signals are detected on the two bus; when there is no communication, the communication processing module is in a completely closed state.

3. The low power system of a smoke sensing chip based on two-bus according to claim 2, characterized in that, The two-bus power data transceiver module is only activated temporarily during the communication stage, and completes data interaction in 1-2 ms, and is in a sleep state for the rest of the time, and the communication processing module is in a closed state.

4. The low power system based on two-bus smoke sensing chip according to claim 1, characterized in that, The counting template first presets a "wake-up threshold N" when counting, and reasonably sets the threshold according to the bus protocol; when the edge counter counts reaches N, a full count signal is output; if CAP_TIMER exceeds the preset time without detecting a new edge before the count reaches N, the counter is automatically cleared and waits for an edge trigger again.

5. The method of using a low power system based on two-bus smoke sensing chip according to any one of claims 1-4, characterized in that, The method comprises the following steps: Step one: in the default state, the MCU, the detection module and the communication module are in a sleep state; when valid data frame start signals are detected on the two bus, for example, a certain voltage appears on the bus voltage through the comparator, an edge interrupt wakes up the MCU, or the MCU is woken up by timing, after waking up, the smoke detection module detects smoke, and after detecting that the smoke exceeds the standard, the communication module uploads alarm data, and then all modules return to the sleep state. Step two: after power on, the chip is initialized, and after initialization, the timing is started, and the sleep is entered. The timing time is the delay between two frames of data when the host polls. After the timing ends, the CPU is woken up, the smoke detection is started, the detected value is compared with the set threshold, and it is judged whether there is smoke. It is detected whether the ID sent by the host is the own ID. If it is not the own ID, it returns to start timing and enter sleep again, waiting for the next wake-up. If the own ID is detected, the smoke or no smoke signal is reported, and then it returns to start timing and enter sleep again, waiting for the next wake-up.

6. The low power system of a smoke sensing chip based on two-bus according to claim 5, wherein, In step two, after power on, the chip is initialized, and the sleep is entered. The valid data frame start signal of the second bus is waited for, and the CPU is woken up by the comparator edge interrupt. After waking up, whether it is 8V is compared first. If it is not, it returns to enter sleep and continue to wait. If it is, the smoke detection is started, the detected value is compared with the set threshold, and it is judged whether there is smoke. It is detected whether the ID sent by the host is the own ID. If it is not the own ID, it returns to enter sleep and wait for the next wake-up. If the own ID is detected, the smoke or no smoke signal is reported, and then it returns to enter sleep and wait for the next wake-up.

7. The low power system of a smoke sensing chip based on two-bus according to claim 5, wherein, In order to make the overall power consumption lower, when communicating with the host, it can also enter the sleep state, and the CPU is woken up by the CAP module edge interrupt to process related events. After the related registers of the CAP capture function are configured, green mode 1 is entered, and the CAP module can still work. After the SLEEP in this mode is executed, the internal high frequency, external low frequency, internal low frequency, and system clock are all in the open state, the instruction clock is in the closed state, or the sleep mode is entered, the clock of each functional module selects the RC400K clock, the internal counter starts working after detecting the edge trigger, the corresponding edge is compared, the interrupt function is completed, and the sleep is entered after the communication with the host, waiting for the next round of smoke detection. The CPU is in the working state only when processing the interrupt service program, and is in the sleep state at other times.

8. The low power system of a smoke sensing chip based on two-bus according to claim 7, characterized in that, MCU first writes a comparison value to the CAPEDGC register, sets the number of sampling edges N; writes two comparison values to CAPCOMP0 and CAPCOMP1, used to compare the width of the level M0 / M1; when the bus voltage code start edge begins, the counter CAP_TIMER starts counting, when the edge is detected, the CAP_TIMER count value is compared with CAPCOMP0 and CAPCOMP1, and the comparison result is stored in the shift register SBUF; if CAP_TIMER>CAPCOMP0, SBUF stores 1, CAPCOMP1<CAP_TIMER<CAPCOMP0, SBUF stores 0; at the same time, the edge counter EDGCNT is incremented by 1, when EDGCNT=CAPEDGC, an interrupt is generated to wake up the CPU, and the value in the shift register SBUF is read out for decoding; after decoding, the CPU returns to sleep immediately, waiting for the next interrupt; a comparison value is written to TMIEROV, when the edge counter EDGCNT does not reach N, the CAP_TIMER exceeds the preset time TMIEROV without detecting a new edge, the counter EDGCNT and the counter CAP_TIMER are automatically cleared, the CPU is woken up, the value in the shift register SBUF is read out for decoding, and the software judges whether the entire sequence has been decoded, whether all tasks have been executed, and immediately returns to sleep again, waiting for the edge trigger.

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