Reference circuit design for telematics devices. The repository contains schematic and white notes. Main modules and controller as MC60(GSM+GPS) and stm32f103 with important points to consider. The purpose of this repository is to share my learning under non-commercial and no derivative purpose to help build strong open source community and giving back to society. The below information is for reference purpose only. I am not liable for the authenticity and accuracy of the details provided here within. Please refer to the datasheets of individual modules/libraries. Below information is important points to consider while designing any schematics and board files.
Below library files can be easly found via key search. MPU-9250. STM32F103C8 EEPROM W25Q16BVSS MC60E BQ24195LRGER LM2596S
Antenna Suggestions:- (For GSM) -a π type matching circuit is suggested to be used to adjust the RF performance -characteristic impedance should be close to 50Ω. input power 50W. Gain (dBi) 1.
(Optional For GSM)
SMA Connector space.
Onboard Antenna with dimension 25x6mm.
(For GPS) -The impedance of RF trace should be controlled as 50Ω, and the trace length should be kept as short as possible. -Passive antenna gain: >0dBi, Active antenna noise <1.5dB (For Active mode in GPS) -Antenna powered by GNSS_VCC with voltage (2.8-4.3v). If voltage does not meet requirements then external ldo be used. -Inductor L1=47nH is used to prevent the RF signal from leaking into GNSS_VCC and amplyfication.
-The effective bandwidth of a GPS antenna is usually measured by the frequency band, below -10dB return loss. The bandwidth of a GPS ceramic patch narrows with size of the patch.
Trace Suggestions:- The VBAT trace should be wide enough to ensure that there is not too much voltage drop during burst transmission. The width of trace should be no less than 2mm; and in principle, the longer the VBAT trace, the wider it will be.
Power consumption -I/P voltage 3.9-17V. (VBUS pin) -I/P current 3A. -O/P Current 4.5A. (SYS pin) -Battery Voltage 4.4V.
PIN DESCRIPTION: Input source VBUS, battery(BAT), or both. FOR detection of input source. D+/D- input source detection to program the input current limit TWO TS pins to monitor the thermistor (NTC) in each cell independently. HIZ- high impedance state STAT- charging status. ILIM- To limit maximum input current on ILIM pin (protection) OTG- CE- Active low Charge Enable pin. TS- Temperature qualification voltage input. Connect NTC BTST- PWM high side driver positive supply. SW- Switching node connecting to output inductor.
blink rate -charging (LOW), charging complete/charge disable(HIGH), charging fault(blinking).
status register REG08[5:4]-> 00 charging disable, 01-precharge, 10-fast charge(const I nd V) 11 charging done.
TS fault register REG09[2:0]
Current in boost mode During boost mode, the status register REG08[7:6] is set to 11, the VBUS output is 5 V and the output current can reach up to 500 mA or 1.3 A, selected via I2C (REG01[0]).
Autonomous charging cycle (i.e without host involvement)
bq24190,bq24192 charging voltage 4.208V ,current 2.048A.
Power Requirements:-
MC60. -GNSS_VCC supply (2.8 - 3.3 - 4.3v). -VRTC power supply (1.5 - 2.8 - 3.3v) backup domain. -VBAT(GSM) Supply Voltage (3.3 - 4.0 - 4.6v). Voltage drop during transmitting burst (400mV). Peak supply current (during transmission slot) 1.6-2A. 577us radio burst in GSM part every 4.615ms. voltage at digital and analog pins (0-3.08v).
STM32F103C8 power (2-to-3.6V).
Relay driver circuit (TQ2SL-L2-5V smd) -> (SC5-S-DC12V through hole) -> latch with 5vdc.
IMU -In MPU6050 for module with ldo(3-5v). -VDD for mpu6050 chip is (2.375-3.46v).
-Buzzer circuit -> . -10-20mA.
-Indicator LED's -Vdd Gsm led 4V 10-20mA. -Vdd Gps led 4V 10-20mA. -Vdd suppply led 1.7V 10-20mA.
Power Regulators:- LM2596 (I/p range is 12-13.6v, o/p is 12v 3amp(max), )
LM1117 (3.3V ) MIC5219 (3.25V 500mA peak o/p ldo) MIC29302 (4.01v 1.6Amps )