Datasheet CAT4101 (ON Semiconductor) - 3
| Hersteller | ON Semiconductor |
| Beschreibung | 1 A Constant-Current LED Driver with PWM Dimming |
| Seiten / Seite | 10 / 3 — CAT4101. Table 4. RECOMMENDED EN/PWM TIMING. Symbol. Name. Conditions. … |
| Dateiformat / Größe | PDF / 220 Kb |
| Dokumentensprache | Englisch |
CAT4101. Table 4. RECOMMENDED EN/PWM TIMING. Symbol. Name. Conditions. Min. Typ. Max. Units. Figure 2. CAT4101 EN/PWM Timing
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CAT4101 Table 4. RECOMMENDED EN/PWM TIMING
(For 3.0 V ≤ VIN ≤ 5.5 V, over full ambient temperature range −40°C to +85°C.)
Symbol Name Conditions Min Typ Max Units
TPS Turn−On time, EN/PWM rising to ILED from ILED = 1 A 1.6 ms Shutdown ILED = 350 mA 1.1 TP1 Turn−On time, EN/PWM rising to ILED ILED = 1 A 920 ns ILED = 350 mA 620 TP2 Turn−Off time, EN/PWM falling to ILED ILED = 1 A 440 ns ILED = 350 mA 310 TR LED rise time ILED = 1 A 840 ns ILED = 350 mA 390 TF LED fall time ILED = 1 A 470 ns ILED = 350 mA 350 TLO EN/PWM low time 1 ms THI EN/PWM high time 5 ms TPWRDWN EN/PWM low time to shutdown delay 8 ms THI TPWRDWN TLO EN/PWM SHUTDOWN SHUTDOWN TP2 TF T T PS T R P1 ILED = (1.2 V / RSET) x 400 90% LED CURRENT 50% 50% SHUTDOWN 0 mA 10% 0 mA VIN QUIESCENT CURRENT SHUTDOWN 0 mA SHUTDOWN
Figure 2. CAT4101 EN/PWM Timing EN/PWM Operation
The EN/PWM pin has two primary functions. One When performing a combination of low frequencies and function enables and disables the device. The other function small duty cycles, the device may enter shutdown mode. turns the LED channel on and off for PWM dimming This has no effect on the dimming accuracy, because the control. The device has a very fast turn−on time (from turn−on time TPS is very short, in the range of 1 ms. EN/PWM rising to LED on) and allows “instant on” when To ensure that PWM pulses are recognized, pulse width dimming LED using a PWM signal. low time TLO should be longer than 1 ms. The CAT4101 Accurate linear dimming is compatible with PWM enters a “zero current” shutdown mode after a 5 ms delay frequencies from 100 Hz to 5 kHz for PWM duty cycle (typical) when EN/PWM is held low. down to 1%. PWM frequencies up to 50 kHz can be supported for duty cycles greater than 10%.
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(For 3.0 V ≤ VIN ≤ 5.5 V, over full ambient temperature range −40°C to +85°C.)
Symbol Name Conditions Min Typ Max Units
TPS Turn−On time, EN/PWM rising to ILED from ILED = 1 A 1.6 ms Shutdown ILED = 350 mA 1.1 TP1 Turn−On time, EN/PWM rising to ILED ILED = 1 A 920 ns ILED = 350 mA 620 TP2 Turn−Off time, EN/PWM falling to ILED ILED = 1 A 440 ns ILED = 350 mA 310 TR LED rise time ILED = 1 A 840 ns ILED = 350 mA 390 TF LED fall time ILED = 1 A 470 ns ILED = 350 mA 350 TLO EN/PWM low time 1 ms THI EN/PWM high time 5 ms TPWRDWN EN/PWM low time to shutdown delay 8 ms THI TPWRDWN TLO EN/PWM SHUTDOWN SHUTDOWN TP2 TF T T PS T R P1 ILED = (1.2 V / RSET) x 400 90% LED CURRENT 50% 50% SHUTDOWN 0 mA 10% 0 mA VIN QUIESCENT CURRENT SHUTDOWN 0 mA SHUTDOWN
Figure 2. CAT4101 EN/PWM Timing EN/PWM Operation
The EN/PWM pin has two primary functions. One When performing a combination of low frequencies and function enables and disables the device. The other function small duty cycles, the device may enter shutdown mode. turns the LED channel on and off for PWM dimming This has no effect on the dimming accuracy, because the control. The device has a very fast turn−on time (from turn−on time TPS is very short, in the range of 1 ms. EN/PWM rising to LED on) and allows “instant on” when To ensure that PWM pulses are recognized, pulse width dimming LED using a PWM signal. low time TLO should be longer than 1 ms. The CAT4101 Accurate linear dimming is compatible with PWM enters a “zero current” shutdown mode after a 5 ms delay frequencies from 100 Hz to 5 kHz for PWM duty cycle (typical) when EN/PWM is held low. down to 1%. PWM frequencies up to 50 kHz can be supported for duty cycles greater than 10%.
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