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NXP Semiconductors UM10525 Скачать руководство пользователя страница 6

UM10525

All information provided in this document is subject to legal disclaimers.

© NXP B.V. 2012. All rights reserved.

User manual

Rev. 1 — 19 April 2012

6 of 21

NXP Semiconductors

UM10525

120 V 20 W CFL demo board using the UBA2212

4. Schematic and functional description

4.1 Functional

description

The bridge rectifier (D1 to D4) rectifies the AC input power. The bulk storage capacitor
C

BUF

filters the rectified DC voltage. Power inductor L

FILT

and capacitor C

BUF

form an LC

filter, which attenuates conducted differential mode EMI noise. Fusible resistor R

fuse

provides protection against overcurrent failure.

During start-up, the internal current source connected to HV pin provides power. Once
capacitor C

DVDT

is charged, it provides the dV/dt supply for normal operation. Capacitor

C

FS

provides the high-side floating supply output and Capacitor C

VDD

is used for VDD

bypass.

C5 and inductor L2 primary winding (N1) form an LC tank translating power into the
burner. The L2 secondary windings N2 and N3 preheat the burner filaments. If preheat is
not required in the application, leave off secondary windings and short the filaments. C8 is
DC blocking capacitor. R

CSI

is used for burner current sensing during boost and RMS

states.

R

osc

and C

osc

determine the nominal oscillating frequency based on the Built-in 555-timer

function. The input to the SW pin generates the V

SW

signal which determines the preheat

time. Capacitor C

CB

sets the boost time.

4.2 Timing

The UBA2212 based 20 W demo board provides all the functions needed for correct CFL
operation. These functions include preheat, ignition, boost and on-state operation.

Several protection features safeguard the correct operation of the CFL and controller IC.
The typical system timing is shown in

Figure 4

.

Fig 3.

Typical UBA2212 Circuit for compact fluorescent lamp application

001aan371

Rfuse

D3

CBUF

C5

C8

C7

C6

L2

RCSI

CDVDT

Cosc

CCB

CVDD

Rosc

CSW

CFS

LFILT

D2

D4

D1

U1

OUT

1

14

FS

SGND

2

13

SGND

HV

3

12

SENSE

PGND

4

11

SGND

DVDT

5

10

CSI

V

DD

6

9

CB

RC

7

8

SW

CFL

AC input

L_N

L_L

UBA2212

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Содержание UM10525

Страница 1: ...emo board using the UBA2212 Rev 1 19 April 2012 User manual Document information Info Content Keywords UBA2212 demo board CFL boost 120 V AC 20 W Abstract This document is a user manual for the UBA221...

Страница 2: ...er manual Rev 1 19 April 2012 2 of 21 Contact information For more information please visit http www nxp com For sales office addresses please send an email to salesaddresses nxp com NXP Semiconductor...

Страница 3: ...CFL warm up and more light after ignition Run up time is one of the key requirements for CFL Normally it is measured from the time lamp was powered until 80 of light output is reached Run up time is l...

Страница 4: ...e using a variable transformer The following symbols identify isolated and non isolated devices WARNING Lethal voltage and fire ignition hazard The non insulated high voltages that are present when op...

Страница 5: ...for 120 V AC 60 Hz Lamp voltage Vlamp steady 100 V measured at 120 V AC mains GE T3 Spiral 20 W burner used Table 2 on page 10 Lamp current Ilamp 170 mA Operating frequency fosc 45 kHz Power Factor 0...

Страница 6: ...tank translating power into the burner The L2 secondary windings N2 and N3 preheat the burner filaments If preheat is not required in the application leave off secondary windings and short the filamen...

Страница 7: ...CCB sweeping cycles The transition from the boost state to the burn state is triggered when the boost timer indicates the end of the boost state During the boost to burn transition the boost transiti...

Страница 8: ...at the boost effect is visible to the human eye when the light is powered up The same situation is not visible when the same lamp is used without boost feature Figure 4 shows the states after power on...

Страница 9: ...UBA2212 1 Ilamp signal 2 SW signal timing for preheat 3 CB signal timing for boost and transition 4 Half bridge voltage Fig 6 Time sequence for a boost lamp with a zoom function applied to the preheat...

Страница 10: ...r point is reached The lamp then enters the burn transition When a lamp burns for a long time is switched off and then after a short delay switched on again The end of boost is reached after only 6 s...

Страница 11: ...acitive mode is detected the internal current source discharges the internal capacitor Consequently the SW voltage is lower and the RMS circuit controlled boost frequency increases until the system is...

Страница 12: ...es the lamp current to be independent of the mains or lamp voltage The lamp current calculation is shown in Equation 2 2 Therefore the boost burn ratio can be found as shown in Equation 3 3 5 3 Overte...

Страница 13: ...turation of the lamp inductor is likely to occur in cost effective and miniaturized CFLs The UBA2212 family internally monitors the power transistor current When the current exceeds the momentary rati...

Страница 14: ...evel The frequency increases very slowly until hard switching is no longer detected Once CMP is no longer active the system increases to the preheating frequency as defined preheat current In boost an...

Страница 15: ...ided in this document is subject to legal disclaimers NXP B V 2012 All rights reserved User manual Rev 1 19 April 2012 15 of 21 NXP Semiconductors UM10525 120 V 20 W CFL demo board using the UBA2212 F...

Страница 16: ...12 SENSE PGND 4 11 SGND DVDT 5 10 CSI VDD 6 9 CB RC 7 8 SW CFL AC input L_N L_L UBA2212 Table 3 Bill of materials Number Reference Typical value Quantity 1 Rfuse 10 1 W no value for fuse resistor 1 2...

Страница 17: ...able 4 with their LC tank start up to burn scope picture and related electrical parameters 16 L2 PC40 EE16 1 5 mH 1 A N 180 6 6 diameter 0 23 mm 1 18 U1 UBA2212CT SO14 1 19 Burner burner T3 Spiral 20...

Страница 18: ...emo board using the UBA2212 Fig 15 12 W Baishi CFL Table 5 Electrical parameters 12 W boost lamp UBA2212BT N1B Boost ratio 1 56 CBUF 22 F 250 V L2 1 75 mH 2 C5 res 7 4 nF 1 kV C6 and C7 100 nF 100 V C...

Страница 19: ...s subject to legal disclaimers NXP B V 2012 All rights reserved User manual Rev 1 19 April 2012 19 of 21 NXP Semiconductors UM10525 120 V 20 W CFL demo board using the UBA2212 9 References 1 UBA2212 H...

Страница 20: ...modification Customers are responsible for the design and operation of their applications and products using NXP Semiconductors products and NXP Semiconductors accepts no liability for any assistance...

Страница 21: ...uded in section Legal information 11 Contents 1 Introduction 3 2 Safety Warning 4 3 Specifications 5 4 Schematic and functional description 6 4 1 Functional description 6 4 2 Timing 6 5 Measurement re...

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