AN2946 datasheet(14/38 Pages) STMICROELECTRONICS

Part #	AN2946

Description	Solar-LED streetlight controller with 25 W LED lamp driver

PDF	38 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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14 / 38 page

Hardware design

AN2946

14/38

Doc ID 15473 Rev 2

Figure 12.

LED lamp driver circuit

3.1.4

Analog signal acquisition circuit

The operating voltage, current and temperature of the battery and LED lamp are monitored

by the MCU. The temperature sensing circuits are illustrated in Figure 13. The voltage and

current sensing circuits are shown in Figure 14. For the battery charger and LED lamp

driver, NTC(s) is soldered on the heat sink of MOSFET (or rectifier). The operating

temperature of the MOSFET (or rectifier) is sensed via NTC(s) and sent to the MCU. These

key power components are protected against overtemperature. For the battery and LED

lamp, the sensing NTC(s) is applied on the battery case and the heat sink of the LED lamp

with wires connected to P4 and P5. For each temperature sensing circuit, a simple RC filter

is added before the signal feeds to the MCU. The temperature sensing is not only for

protection but also applicable for charge pattern optimization online. The battery life is

prolonged.

AN2946 Datasheet(PDF) 14 Page - STMicroelectronics