EVL6562A-LED STMicroelectronics, EVL6562A-LED Datasheet - Page 11

• Manufacturer Part Number: EVL6562A-LED
• Description: EVALUATION MODULE L6562A
• Manufacturer: STMicroelectronics
• Type: Power Factor Correctionr

Specifications of EVL6562A-LED

• Current - Output / Channel: 350mA
• Outputs And Type: 1, Non-Isolated
• Features: Dimmable
• Voltage - Input: 48V
• Utilized Ic / Part: L6562A
• Input Voltage: 48 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6562A
• Other names: 497-10420

AN2983
2.4
If we consider the time at which the capacitor voltage crosses the 0.7 V threshold, the
equivalent toff time is 1.32 µS (+150 nS compared to the nominal value, due to the tolerance
of C8 and stray capacitance) while the remaining 250 nS are related to the propagation
delay (during which the voltage falls from 0.7 V to 0.44 V).
Figure 10. toff delay (nominal)
Current setting
As already indicated, the CS pin of the L6562A controller is internally connected to the non-
inverting input of the CS comparator, whose threshold (Vth) is fixed to 1.08 V (nom.)
Tying it to the sense resistor forces the comparator’s output high when I_Led = Vth / RS.
This is a very simple way to detect – and limit – the peak load current to a fixed value.
In order to make this value adjustable, we can introduce an auxiliary voltage source (Va),
connected to the CS pin through a resistor (Ra) and another resistor (Rb) between CS and
the sense resistor, as indicated in
modify the threshold at which the (peak) load current triggers the comparator.
Figure 11. Current setting
Doc ID 15679 Rev 1
Figure 11
. In this way the auxiliary source can be used to
CH(1) red=V_GD;
CH(4) green=I_LED;
CH(2) blue=V_C8;
Traces:
Circuit description
AM04261v1
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