UBA2071_A_1

© NXP B.V. 2008. All rights reserved.

Product data sheet

Rev. 01 — 23 June 2008

10 of 35

NXP Semiconductors

UBA2071; UBA2071A

Half bridge control IC for CCFL backlighting

initial ignition frequency sweep and normal operation mode. Figure 6, EN configuration,

shows three examples of how the enable input can be used:

1. Digital enable input with DC blocking capacitor charging. R1 and C1 define a fixed

DC blocking capacitor charging time.

Remark: The digital input signal high level has to be above the maximum value of

2. Sensing of HV supply and DC blocking capacitor voltages via the EN pin. The IC will

above

. It will then go into initial ignition frequency

.

3. Sensing of HV supply and DC blocking capacitor voltages via the EN pin combined

with digital enable input.

during which both power switches are off. This is repeated until the mode is left. When

the running cycle of the DC blocking capacitor charging mode will first be completed (see

Figure 7).

3.

When the enable input is kept high during the time that the IC is off, because the supply voltage is too low, the IC might not start in

DC blocking capacitor charging mode.

Fig 6.

EN configuration

014aaa253

UBA2071

EN

C1

R1

enable

(1)

UBA2071

EN

R4

(2)

R3

R2

Cblock

UBA2071

EN

R4

(3)

R3

R2

Cblock

R5

disable

R2/R4

()

R2/R3

() 1

++

() V

th(H)1(EN)

×

R4/R2

()

R4/R3

() 1

+

+

() V

th(H)2(EN)

R4/R2

V

HV

×

–

×

()