AN3372 Datasheet, PDF (21/37 Pages) STMicroelectronics – This note describes digital ballast for 70 W HID lamps

AN3372
ST7 microcontroller application pin use
Figure 12. Reset circuit
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The net connected to the RST pin is composed of R37 = 47 kΩ and C16 = 100 nF. This net
is used to detect if the reference voltage has reached 5 V. The MCU gives a reset if the +5 V
level voltage is not reached.
● Pin 7: not used
● Pin 8: VDD MCU supply voltage
● Pin 9: GND
● Pin 10: not used
● Pin 11: not used
● Pin 12: GND
● Pin13: VDD MCU supply voltage. It is obtained using the Vref pin of the L6382D5 and
is able to supply 5 V with ± 2% of tolerance
● Pin 14: MCU analogue input channel 0 used for PFC Vout measurement. A resistor
divider is connected at the PFC output in order to obtain the feedback signal. It is
designed to obtain a voltage compatible with 5 V MCU voltage.
The net for Vbus measurement is shown in Figure 13.
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