美芯电动窗户防夹系统参考设计

美芯公司的电动窗户防夹(Anti-Pinch)系统APGRD002参考设计包括14引脚的MCU器件PIC16F688和完全的H桥控制器,10位ADC以及集成了LIN协议模块.其中的H桥控制器和10位ADC提供了双向马达控制,以及用来实现窗户防夹的有源反馈.集成的LIN协议模块可以是门窗模块和车体控制器进行通信.这些特性的组合是电动车窗的理想解决方案.本文介绍了APGRD002参考设计的主要性能, 带电压稳压器的MCP201 LIN 收发器性能, PIC16F688 性能以及参考设计的详细电路图.

Microchip Window Lift w/Anti-Pinch Reference Design
Looking for a flexible, cost effective solution for Window Lift with Anti-Pinch? The APGRD002 Window Lift Reference Design maybe just what you are looking for. This kits features the PIC16F688, a 14 pin device, with a Full H-Bridge controller, 10-bit ADC and an integrated LIN Protocol module. This feature set combines to make an ideal solution for Window Lift applications. The H-Bridge controller and the 10-bit ADC coupled to provide bidirectional motor control with active feedback for implementing the Anti-Pinch functionality. The Integrated LIN Protocol Module allows for intersystem communication with in the door module as well as the main body controller.



APGRD002的主要特性:
The APGRD002 Reference Design Kit consists of a microcontroller, 5 volt regulator, relays and drivers, input conditioning circuitry, and network physical layer interface.
All documentation is available on the CD-ROM for APRD002;Firmware, Schematics, Gerber files, Assemble Diagrams and BOM
Firmware is designed for a Window Lift with Anti-Pinch application
The APGRD002 Reference Design serves as a target board for LIN bus communication. Switch inputs, as well as LIN commands, can be used to control the two output relays for driving an H-bridge Motor configuration or a simple Servo circuit.

一.带电压稳压器的MCP201 LIN 收发器性能介绍
The MCP201 provides a physical interface between a microcontroller and a LIN half-duplex bus. It is intended for automotive and industrial applications with serial bus speeds up to 20 Kbaud.
The MCP201 provides a half-duplex, bidirectional communications interface between a microcontroller
and the serial network bus. This device will translate the CMOS/TTL logic levels to LIN level logic, and vice versa.

The LIN specification 1.3 requires that the transceiver of all nodes in the system be connected via the LIN pin, referenced to ground and with a maximum external termination resistance of 510from LIN bus to battery supply. The 510corresponds to 1 Master and 16 Slave nodes.

The MCP201 provides a +5V 50 mA regulated power output. The regulator uses a LDO design, is shortcircuit- protected and will turn the regulator output off if it falls below 3.5V. The MCP201 also includes thermal shutdown protection. The regulator has been specifically designed to operate in the automotive environment and will survive reverse battery connections, +40V load dump transients and double-battery jumps.

主要特性:
Supports baud rates up to 20 Kbaud
40V load dump protected
Wide supply voltage, 6.0 – 18.0V, continuous
- Maximum input voltage of 30V
Extended Temperature Range: -40°C to +125°C
Interface to standard USARTs
Compatible with LIN Spec 1.3
Local Interconnect Network (LIN) Line pin:
Internal pull-up resistor and diode
- Protected against ground shorts (LIN pin to ground)
- Protected against LIN pin loss of ground
- High current drive, 40 mA ≤IOL ≤200 mA
Automatic thermal shutdown
On-board Voltage Regulator:
- Output voltage of 5V with ±5% tolerances over temperature range
- Maximum output current of 50 mA
- Able to drive an external series-pass transistor for increased current supply capability
- Internal thermal overload protection
- Internal short-circuit current limit
- External components limited to filter capacitor only and load capacitor



图2. MCP201方框图.



图3. MCP201的应用电路图.
二.PIC16F688 性能介绍
14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology
高性能RISC CPU
Only 35 instructions to learn:
- All single-cycle instructions except branches
Operating speed:
- DC – 20 MHz oscillator/clock input
- DC – 200 ns instruction cycle
Interrupt capability
8-level deep hardware stack
Direct, Indirect and Relative Addressing modes
特殊的微控制器特性:
Precision Internal Oscillator:
- Factory calibrated to ±1%
- Software selectable frequency range of 8 MHz to 31 kHz
- Software tunable
- Two-Speed Start-up mode
- Crystal fail detect for critical applications
- Clock mode switching during operation for power savings
Power saving Sleep mode
Wide operating voltage range (2.0V-5.5V)
Industrial and Extended temperature range
Power-on Reset (POR)
Power-up Timer (PWRT) and Oscillator Start-up Timer (OST)
Brown-out Detect (BOD) with software control option
Enhanced Low-Current Watchdog Timer (WDT) with on-chip oscillator (software selectable
nominal 268 seconds with full prescaler) with software enable
Multiplexed Master Clear with pull-up/input pin
Programmable code protection
High-Endurance Flash/EEPROM cell:
-100,000 write Flash endurance
-1,000,000 write EEPROM endurance
-Flash/Data EEPROM retention: > 40 years
低功耗特性:
Standby Current:
- 1 nA @ 2.0V, typical
Operating Current:
- 8.5A @ 32 kHz, 2.0V, typical
- 100A @ 1 MHz, 2.0V, typical
Watchdog Timer Current:
- 1A @ 2.0V, typical
外设特性:
12 I/O pins with individual direction control:
- High-current source/sink for direct LED drive
- Interrupt-on-pin change
- Individually programmable weak pull-ups
- Ultra Low-Power Wake-up
Analog comparator module with:
- Two analog comparators
- Programmable on-chip voltage reference (CVREF) module (% of VDD)
- Comparator inputs and outputs externally accessible
A/D Converter:
- 10-bit resolution and 8 channels
Timer0: 8-bit timer/counter with 8-bit programmable prescaler
Enhanced Timer1:
- 16-bit timer/counter with prescaler
- External Gate Input mode
- Option to use OSC1 and OSC2 in LP mode as Timer1 oscillator if INTOSC mode selected
Enhanced USART Module:
- Supports RS-485, RS-232, and LIN 1.2
- Auto baud detect
- Auto-wake-up on Start bit
In-Circuit Serial Programming™ (ICSP™) via two pins

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图4.PIC16F6888方框图。

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图5.参考设计电图.