Delta Electronics 6A Series manual Features Descriptions CON, Output Voltage Programming

FEATURES DESCRIPTIONS (CON.)

The ENABLE input can be driven in a variety of ways as shown in Figures 18 and 19. If the ENABLE signal comes from the primary side of the circuit, the ENABLE can be driven through either a bipolar signal transistor (Figure 19).If the enable signal comes from the secondary side, then an opto-coupler or other isolation devices must be used to bring the signal across the voltage isolation (please see Figure 20).

ND6A/10A

NE6A/10A

Output Voltage Programming

The output voltage of the NE series is trimmable by connecting an external resistor between the trim pin and output ground as shown Figure 21 and the typical trim resistor values are shown in Figure 22.

ND 6A/10A

NE6A/10

Vin Vout

Trim

Enable

Vin

Vout

Rs

Ground Ground

Enable Trim

Ground Ground

Figure 19: Enable Input drive circuit for NE series

NDNE6A/10A

Figure 21: Trimming Output Voltage

The NE06 module has a trim range of 0.59V to 5.0V. The trim resistor equation for the NE06A is :

Rs(Ω) = 1184

Vout 0.592

Vin Enable

Vout

Trim

−

Vout is the output voltage setpoint

Ground Ground

Figure 20: Enable input drive circuit example with isolation.

Input Under-Voltage Lockout

The input under-voltage lockout prevents the converter from being damaged while operating when the input voltage is too low. The lockout occurs between 2.8V to 3.1V.

Over-Current and Short-Circuit Protection

Rs is the resistance between Trim and Ground Rs values should not be less than 240Ω

Output Voltage	Rs (Ω)
0.59V	open
+1 V	2.4k
+1.5 V	1.3K
+2.5 V	619
+3.3 V	436
+5.0V	268

Figure 22: Typical trim resistor values

The NE series modules have non-latching over-current and short-circuit protection circuitry. When over current condition occurs, the module goes into the non-latching hiccup mode. When the over-current condition is removed, the module will resume normal operation.

An over current condition is detected by measuring the voltage drop across the MOSFETs. The voltage drop across the MOSFET is also a function of the MOSFET’s Rds(on). Rds(on) is affected by temperature, therefore ambient temperature will affect the current limit inception point.

The detection of the Rds(on) of MOSFETs also acts as an over temperature protection since high temperature will cause the Rds(on) of the MOSFETs to increase, eventually triggering over-current protection.

DS_NE12S06A_06302008 7