Datasheet TSM1012 (STMicroelectronics) - 8

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Principle of operation and application hints TSM1012 Equation 4
Plim = Vsense x Ilim Therefore, for most adapter and battery charger applications, a quarter-watt, or half-watt resistor to make the current sensing function is sufficient. The current sinking outputs of the two transconductance operational amplifiers are common (to the output of the IC). This makes an ORing function which ensures that whenever the current or the voltage reaches too high values, the optocoupler is activated. The relation between the controlled current and the controlled output voltage can be described with a square characteristic as shown in the following V/I output-power graph.
Figure 4. Output voltage versus output current
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6.2 Compensation
The voltage control transconductance operational amplifier can be fully compensated. Both of its output and negative input are directly accessible for external compensation components. An example of a suitable compensation network is shown in Figure 6. It consists of a capacitor Cvc1 = 2.2 nF and a resistor Rcv1 = 22 K in series. The current control trans conductance operational amplifier can be fully compensated. Both of its output and negative input are directly accessible for external compensation components. An example of a suitable compensation network is shown in Figure 6. It consists of a capacitor Cic1 = 2.2 nF and a resistor Ric1 = 22 K in series. 8/14 DocID10124 Rev 2 Document Outline Figure 1. Pin connections (top view) Table 1. Order codes 1 Pin descriptions Table 2. SO-8 pinout 2 Absolute maximum ratings Table 3. Absolute maximum ratings 3 Operating conditions Table 4. Operating conditions 4 Electrical characteristics Table 5. Electrical characteristics 5 Internal schematics Figure 2. Internal schematic Figure 3. Typical adapter or battery charger application using TSM1012 6 Principle of operation and application hints 6.1 Voltage and current control 6.1.1 Voltage control 6.1.2 Current control Figure 4. Output voltage versus output current 6.2 Compensation 6.3 Start-up and short-circuit conditions 6.4 Voltage clamp Figure 5. Clamp voltage Figure 6. Typical application schematic 7 Package information 7.1 SO-8 package information Figure 7. SO-8 package outline Table 6. SO-8 package mechanical data 8 Revision history Table 7. Document revision history