Part # Application Note Display Monitor STSA1805 STN790A AN1722 datasheet

Part Manufacturer: ST Microelectronics

ST Microelectronics

Part Description: Design and realization of a CCFL application using TSM108, STN790A, OR STS3DPFS30, and STSA1805


Part Details:

AN1722 APPLICATION NOTE Design and Realization of a CCFL Application Using TSM108, STN790A, or STS3DPFS30, and STSA1805 1. ABSTRACT This technical document shows how to use the integrated circuit TSM108, the PNP power bipolartransistor STN790A, or the P channel power MOSFET STS3DPFS30, the NPN power bipolar transistorSTSA1805 and the diode 1N5821 in order to design and realize a CCFL application. Such work allowsSTMicroelectronics customers to choose an alternative design and STMicroelectronics itself to supply alldevices concerning the power transistor part and also the control and driver part for these applications(KIT approach). In the application block diagram below, the several STMicroelectronics power devices are inserted in therelated block. Figure 1: Block diagram of the application BUCK SECTION +12V STN790A 1N5821 STS3DPFS30 PUSH-PULL SECTION STSA1805 OUTPUT SECTION PWM SECTION TSM108 LAMPS 2. TSM108 DESCRIPTION TSM108 is a PNP power bipolar or P channel power MOSFET controller. TSM108 includes a PWMgenerator (AMP3 in fig. 2), voltage and current control loops (AMP1 and AMP2 respectively in fig. 2) andit also includes safety functions that lock the PNP power bipolar or P channel power MOSFET in offstate. The TSM108 can sustain 60V on Vcc and the Isink (base or gate drive sink current to switch on thedevice) and Isource (base or gate drive source current to switch off the device) are respectively 15 mA(min value) and 30 mA (max value). Rev. 2 June 2004 1/56 AN1722 - APPLICATION NOTE Figure 2: TSM108 schematic circuit As exposed above, the safety functions UV and OV can switch off the power transistor (PNP power bipolaror P channel power MOSFET) when the Vcc is under a definite min voltage or when the Vcc overcomes adefinite max voltage. In fact, in these cases the output signal of the AMP 5, or the AMP 6, is low and theNAND output is high. Considering the UV function, fig. 3 shows the circuit part concerning it. Figure 3: UV schematic circuit detail 184k 76.5k 2.52V The V+ voltage (the one in the non-inverting pin of the AMP5) is: 76.5 V = V + (1.1) cc 184 + 76.5 and considering: V-=2.52V (1.2) 2/56 AN1722 - APPLICATION NOTE the minimum Vcc under which the application will switch off is: 2 52 . V = 184 ( + 76 5 . ) 8 5 . V (1.3)


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Application Note Display Monitor STSA1805 STN790A AN1722.pdf Datasheet