FREQUENTLY ASKED QUESTIONS Find answers to common questions or email us Power Part滥情滴s时代无弹窗全文阅读 滥情滴s时代最新章节,ribenrentiyishu最新章节目录 ribenrentiyishu无弹窗 1.1 Is it possible to use diod
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Find answers to common questions or email us
Power Part滥情滴s时代无弹窗全文阅读 滥情滴s时代最新章节
1.1 Is it possible to use diode to convert 5V to 4.4V for power supply?
It is not recommended to use this method, because the forward voltage of diode will change as the current changes, which will cause the instability of the module’s power supply and make the module work abnormally.It is not recommended to use this method, because the forward voltage of diode will change as the current changes, which will cause the instability of the module’s power supply and make the module work abnormally.
1.2 Is it possible to use standard USB to supply power for the module?
The output current of standard USB interface is max.500mA, which does not meet the peak current demand of GPRS module. If USB interface is required to supply power for the module, you can operate like below:
1) Use AT+QGPCLASS to set the GPRS level to 8. This command will take effect after next restart of the module. There is only one uplink slot when the GPRS level is 8.
2) Connect two 2200uF capacitors with low ESR value to VBAT pin and keep them close to the module.
3) It is recommended that the VBAT voltage should be adjusted between 4.2V and 4.5V which can prevent the module from working abnormally due to the voltage drop of VBAT.
4) Test the module under the weak signal environment (such as CSQ value is less than 14). If the module works properly, it indicates that USB interface can supply power for the module.
1.3 How to use higher DC voltage (e.g. automotive 12V/24V/48V) to power the module?
It is suggested to implement it by two stage conversion. First stage is to step down to 5V via DC-DC converter and the second stage is to convert to 4V from 5V via LDO as shown in the figure below.
1.4 How to test the power consumption in the sleep mode?
The best way to test the power consumption of module is to supply power for module separately in case that peripheral circuit might cause extra power consumption.ONLY VBAT/GND/SIM/RF/PWRKEY should be connected, in this case, the power consumption on VBAT will be the exact consumption of module.
To test the power consumption on the EVB board, please operate like below:
(1) Remove the resistor R110 and R102.
(2) Solder R224 with a 0Ω resistor.
(3) Plug the power adapter and turn on the 5V power switch. See figure below.
1. Removing R110 is to make sure that the power supply of module is directly from the external power via J103.
2. Power adapter should be plugged to offer the power for the RS232 converter and LEDs, which will avoid the increase of power consumption caused by sink current.
3. VDD_EXT of module is used to supply the power for RS232 converter. In order to avoid the RS232 converter being supplied by VDD_EXT, R102 should be removed. Meanwhile, R224 should be soldered a 0R resister to supply the power for RS232 converter with 5V power adapter.
2.1 How to deal with the UART communication failure?
First of all, check the level of STATUS pin to judge whether the module is powered on or not. High level means the module is on and low level means the module is off. If module has already been powered on, you need to analyze it according to the following two situations.