DS3994应用电路

DS3994应用电路 Application with a single lamp per channel

In this application the internal DC bias voltage at the LCM and OVD pins allows for an AC-coupled input. This design can make the external circuitry very simple. A typical operating circuit for this application is shown in Figure 1.


Figure 1. Typical operating circuit with a single lamp per channel.

In this application, the thresholds are referenced to V_DCB. The values are listed in Table 2 and may be different for other parts.
Table 2. DS3994 LCM and OVD Thresholds (for Figure 1)

Parameter	Symbol	Min	Typ	Max	Units
Lamp off threshold	VLOT	0.30	0.40	0.50	V
Lamp overcurrent threshold	VLOC	1.80	2.00	2.20	V
Lamp regulation threshold	VLRT	0.94	1.00	1.06	V
OVD threshold	VOVDT	0.90	1.00	1.10	V