HV9982DB1 Supertex, HV9982DB1 Datasheet - Page 7

• Manufacturer Part Number: HV9982DB1
• Manufacturer: Supertex

Specifications of HV9982DB1

• Lead Free Status / Rohs Status: Supplier Unconfirmed

PWM Dimming Operation – PWM Dimming operation with an external TTL square wave signal is shown in Figs. 10-12.
Fig. 10 shows the overall operation of the circuit with a PWM dimming input and Figs. 11 and 12 show the rise and fall times
of the LED current during PWM dimming.
In some cases, depending on the parasitic capacitance of the LED string, there may be narrow spike in the LED current
during the rising edge. To prevent this spike from shutting down the HV9982 due to a short circuit condition being falsely
detected, an internal 500ns blanking is provided in the IC. Fig. 13 shows the rising edge of the PWM dimming operation of
the same LED driver with a different LED load (which has a signifi cant parasitic capacitance).
Fig. 10: PWM Dimming
Fig. 11: PWM Dimming – Rise Time
Fig. 12: PWM Dimming – Fall Time
C1 (Yellow): PWM Dimming Input for Channel 1(5V/div)
C4 (Green):
Time Scale: 1μs/div
C1 (Yellow): PWM Dimming Input for Channel 1(5V/div)
C4 (Green):
C1 (Yellow): PWM Dimming Input for Channel 1(5V/div)
C4 (Green):
Time Scale: 1μs/div
Time Scale: 500μs/div
Output Current for Channel 1 (50mA/div)
Output Current for Channel 1 (50mA/div)
Output Current for Channel 1 (50mA/div)
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HV9982DB1