VIN

VCC

8V - 15V (from

power stage)

C1

LM5032

9V

0.1

0.1 2F

50

LM5032

VIN

LM5032

SNVS344B – MARCH 2005 – REVISED DECEMBER 2014

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

8.1.1 VIN

The voltage applied to the VIN pin, normally the same as the system voltage applied to the power transformer’s

depends primarily on the output driver capacitive loads, the switching frequency, and any external load at VCC. If

the power dissipation associated with the VIN current exceeds the package capability, an external voltage should

be applied to VCC (see Figure 2 & Figure 3) to reduce power in the internal start-up regulator. It is recommended

the circuit of Figure 19 be used to suppress transients which may occur at the input supply, in particular where

VIN is operated close to the maximum operating rating of the LM5032.

When all internal bias currents for the LM5032 and output driver currents are supplied through VIN and the

enabled and the external VCC supply voltage is active, the current into VIN then drops to a nominal 120 µA.

Figure 19. Input Transient Protection

8.1.2 For Applications > 100 V

start-up regulator as shown in Figure 20, or from any other low voltage source as shown in Figure 21.

Connecting VIN and VCC together allows the LM5032 to be operated with VIN below 13V. The voltage at VCC

must not exceed 15V. The voltage source at the right side of Figure 20 is typically derived from the power stage,

and becomes active once the LM5032’s outputs are active.

18

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