BELLING BL8305A Ballast control ic Datasheet

BL8305A BALLAST CONTROL IC
The ballast control IC BL8305A is an improved version of the BL8301. The BL8305A
provides more functionality and is easier to use than previous IC BL8301. The BL8305A
optimizes the compatibility of driving MOSFET half-bridge (MHF
MHF)
MHF or Bipolar
half-bridge
(BHF
BHF).
BHF
Especially
for
Bipolar
half-bridge,
the
BL8305A
can
automatically adjust the base current intensity (BCI
BCI AutoAuto-Adj),
Adj and
guarantee that the half-bridge is in the optimum condition and reduces
the power loss of half-bridge. It also improves the load adaptive of
bipolar half-bridge. The BL8305A changes the timing component
connection structure according to BL8301, so it is easier to design
simply dimming products. The BL8305A has fully protections and all
pins have Latch immunity and ESD protection, available in both PDIP14
and SOP14 packages.
FEATURES
Driving both MHF and BHF
Automatically adjusting the BCI of BHF
Programmable preheat frequency, preheat time and run frequency
Comprehensive protection
Micro power startup less than 150uA
Latch immunity and ESD protection
BRIEF INTRODUCTION
1. The BL8305A automatically provides a dead time 3us for BHF and 1.2us
for MHF.
2. The BL8305A features include on power preheat and ignition. Preheat
frequency, preheat time and run mode frequency are all programmable by
external components.
3. Comprehensive protections such as protection from over current of
Half-bridge, filament failures, ignition failure, end of life,
detecting base current of half-bridge and so on.
4. The BL8305A have an internal power regulator at 6.35V and micro power
startup less than 150uA.
5. The BL8305A is a low cost design for ballast with few external
components.
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BL8305A BALLAST CONTROL IC
6. The BL8305A is available in both PDIP14 and SOP14 packages. All pins
have Latch immunity and ESD protection.
APPLICATION INFORMATION
400V
IN4148
Rstart
1n
RHV
430K
15V
1M
13005
BL8305A
Rp2
Rt
Ct
0.1u
Rpre
HV
Rt
Ct
LD
FD
Cpre
Pro
POFF
2
Ro 30
22
22n
13005
10
Co 47n
2
22n
IN4148 100K
GND
Cp
620K
C1
470p
4.7u
17.2K
100K
Rp1
OUT1
OUT2
0.1u
Vcc
Vdc
175K
FR107
10
100n
2mH
T8
FR107 36W
8.2n
0.1u
2
Attention: This shematic for T8 36W only, other types lamp should change some components
Fig. 1
400V
IN4148
Rstart
1M
1n
15V
IRF830
100
BL8305A
Rp2
Rt
Ct
0.1u
Cp
Vdc
OUT2
Rpre
Rt
HV
LD
Ct
FD
Cpre
POFF
Pro
GND
Co
1u
IRF830
100n
2mH
100
T8
36W
620K
C1
470p
4.7u
17.2K
100K
Rp1
OUT1
0.1u
175K
Vcc
8.2n
0.1u
2
Attention: This shematic for T8 36W only, other types lamp should change some components
Fig. 2
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BL8305A BALLAST CONTROL IC
BLOCK DIAGRAM
LEAD ASSIGNMENTS & DEFINITION
Pin#
1
2
3
Symbol
VCC
VDC
Rpre
4
5
6
7
8
9
10
11
12
13
14
Rt
Ct
Cpre
POff
GND
Pro
FD
LD
HV
OUT2
OUT1
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Description
Power Supply
6.3V regulator output
Preheat frequency timing
voltage
Oscillator timing resistor
Oscillator timing capacitor
Preheat timing capacitor
End of preheat output
IC power &signal ground
Current sensing input
Filament detection input
Window discriminator input
Half-bridge output sense
OUTPUT2
OUTPUT1
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BL8305A BALLAST CONTROL IC
FUNCTION DESCRIPTION
StartStart-up and Power Supply
When the VCC is below the turn-on threshold of the IC, the BL8305A is in the
low power consumption mode, oscillator and half-bridge are shut off. The start-up
capacitor (C1) is charged by 400V DC-BUS
through resistor (Rstart). The charge current
(Icharge) is the current through Rstart minus
the start-up current (IQstart) drawn by the
IC. So the choice basis of starting resistance
Rstart is: In most abominable cases, the
current guaranteeing to pass Rstart is
IQStart of twice at least.
Once the capacitor voltage on VCC reaches the start-up threshold, the IC turns
on and the output turns on. The rectified current charges the capacitor at about
15V. The recommended capacitor value is 22uF.
Preheat Mode, Ignition Mode and Run Mode
The Preheat frequency, preheat time and run mode frequency of BL8305A are all
programmable by external components. The typical frequency vs. time curve is as
the picture shows.
The preheat time is set by the external capacitor Cp. An internal current source
ICpreCharge charges Cp when the IC
started. The frequency remains at
eh preheat frequency until the
voltage on Cp over the threshold
voltage. After preheat the BL8305A
begins to igniting the lamp. The
total
preheat
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time
is:
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BL8305A BALLAST CONTROL IC
T preheat = 0.203 × C p × 10 7 − 0.249 *
voltage(VRpre)
VR Pr e =
at
R pre 2
R pre1 + R pre 2
pin3,
the
R p2
R p1 + R p 2
preheat
sec。Preheat frequency is set by the
frequency
is:
f pre =
VRpre
1 .6
× f run ,
× 6.35
. The run mode oscillating frequency is determined by the
timing resistor RT and timing capacitor Ct, f run =
0.374
。
Rt × Ct
Drive BHF or MHF
When driving BHF, a transformer with two secondary magnifies the output current
of BL8305A and the half-bridge is drive by the magnified current. The output voltage
of half-bridge is divided by the resistor RHV and an internal resistor about 40Kohm
in the PIN HV and the BL8305A senses this waveform, and automatically adjusts the
BCI. The BCI Auto-Adj is enabled at about 1 sec after the ignition. As showing in
the figure, if BCI is appropriate, the output of BL8305A will be remain as the black
line; if BCI is low, the output of BL8305A will be increase as the dashed line;
if BCI is over driving, the output of BL8305A will be decrease as the dashdotted
line.
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BL8305A BALLAST CONTROL IC
Driving MHF the output connection is shows as the figure above. The driving
voltage is coupled from out1 by a 1:2 transformer in order to separate the IC
form high voltage. In MHF driving configuration, HV is connect to GND directly,
hence whether the BL8305A in preheat, ignition or run mode the output of BL8305A
is fixed.
Fault Protection
The BL8305A provides 3 leads to sensing fault: Pro (PIN9), FD (PIN10) and LD
(PIN11).
The Pro PIN is enabled at the IC turns on. Once the voltage at this pin exceeds
Vpro (0.55V), the IC enters fault mode and both outputs are latched in the ‘low’
state.
The FD PIN is used for filament detection; the IC will be restart when FD received
a pulse.
LD is a window discriminator. The high threshold
is 4.3V, and the low threshold is 2.0V. LD has a pull
up resistor 200K to Vdc, and a pull down resistor 200K
to GND, in order to get a bias voltage 3.2V for the LD
PIN. At the end of ignition mode, LD will become
effective after 1s delay(1s delay is used for avoid
ignition’s burr).
Once the BL8305A enters the fault mode, the IC will
lock the state until VCC recycles back below the shut
down threshold or the filament detection PIN, SD, receives a pulse.
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BL8305A BALLAST CONTROL IC
Filament Preheat Voltage Remove
The BL8305A provides a control signal (PIN Poff) to switch off the filament
preheat voltage. When it done with the ignition and turns into run mode, Poff will
output a high level after about 1s delay (drive ability 20mA). This high level can
close the switch K and turn off the filament voltage.
ABSOLUTE
ABSOLUTE MAXIMUM RATIONS
Absolute maximum ratings indicate sustained limits beyond which damage to the
device may occur. All voltages parameter are absolute voltages referenced to
GND, all current are defined positive into any lead.
Parameter
Min.
Max
Units
Symbol
Definition
Vcc(1)
Supply voltage
---
30
V
VRpre
Preheat frequency timing voltage
1
7
V
IRt
Oscillator output current
---
1
mA
VPro
Current sensing voltage
-0.3
Vdc
V
Iout1
Output current of Out1
200
mA
Iout2
Output current of Out2
200
mA
TS
Storage temperature
150
℃
-55
Note 1: Only for BHF mode. In MHF mode VCC should less than 15V.
RECOMMENDED OPERATING CONDITIONS
Parameter
Min.
Typ.
Max.
Units
Symbol
Definition
Vcc
Supply voltage
--
15
--
V
VRpre
Preheat frequency timing voltage
1
--
4
V
IRt
Oscillator output current
20
82
200
uA
VPro
Current sensing voltage
0
--
Vdc
V
ELECTRICAL CHARACTERISTICS
TA=25℃,VCC=15V,Rpre1=150K,Rpre2=100K,Rt=17.7K,Ct=470pF,Cp=0.1uF,Vpro=0V,
VLD1= 3.2V,VHV=0
Parameters
Symbol
Min.
Typ.
Max.
Units
Test Condition
Definition
Power Supply Characteristics
VCCon
Power on Voltage
-
13.7
-
V
VCC rising from 0V
VCCoff
Shut down voltage
-
10
-
V
VCC falling from
15V
VDC
Internal power
regulator output
-
6.35
-
V
VCC=15V
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BL8305A BALLAST CONTROL IC
voltage
IVDC
Internal power
regulator output
current
IQStart
Low power startup
current
---
IQFault
Fault protection
quiescent current
IQVCC
Quiescent current
Oscillator Characteristics
fosc
Oscillator frequency
VCT
Oscillator capacitor
voltage
Preheat Characteristics
ICpreCharge
Cpre charge current
10
mA
VCC=15V
---
150
uA
VCC<VCCon
---
---
250
uA
Pro > 0.55V or
LD < 2.0V or
LD > 4.3V
---
3
---
mA
Out1、Out2 Without
load
1
---
300
KHz
---
45
---
KHz
4
V
2
---
0.45
---
uA
---
0.97
---
uA
ICpreDis
Cpre discharge
current
Fpre
Preheat frequency
71
KHz
Tpre
Preheat time
1.4
S
Tign
Ignition time
140
mS
VCpreFault
Cpre voltage under
fault protection
---
Driver Output Characteristics (HV=GND)
Vout1p-p p-p output voltage of
13
out1
fosc = 45 KHz
0
---
V
---
15
V
Iout > 100mA
Iout1
p-p output current of
out1
-
---
200
mA
Vout1p-p > 13V
Vout2p-p
p-p output voltage of
out1
13
---
15
V
Iout > 100mA
Iout2
p-p output current of
out1
-
---
200
mA
Vout1p-p > 13V
TdeadMOS
Dead time for MHF mode
1.2
us
TdeadBip
Dead time for MHF mode
3.0
us
Protection Characteristics
VPro
Over current sensing
threshold
-
0.55
-
V
VLDup
High threshold of LD
-
4.3
-
V
VLDdn
Low threshold of LD
-
2.0
-
V
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HV=6.3V
8/28/2006
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