Micro Linear ML4835CS Compact fluorescent electronic dimming ballast controller Datasheet

July 2000
PRELIMINARY
ML4835*
Compact Fluorescent Electronic Dimming
Ballast Controller
GENERAL DESCRIPTION
FEATURES
The ML4835 is a complete solution for a dimmable or a
non-dimmable, high power factor, high efficiency
electronic ballast especially tailored for a compact
fluorescent lamp (CFL). The Bi-CMOS ML4835 contains
controllers for “boost” type power factor correction as
well as for a dimming ballast with end-of-lamp life
detection.
■
Power detect for end-of-lamp-life detection
■
Low distortion , high efficiency continuous boost, peak
or average current sensing PFC section
■
Leading- and trailing-edge synchronization between
PFC and ballast
■
One to one frequency operation between PFC and
ballast
■
Programmable start scenario for rapid/instant start lamps
■
Triple frequency control network for dimming or
starting to handle various lamp sizes
■
Programmable restart for lamp out condition to reduce
ballast heating.
■
Internal over-temperature shutdown
■
PFC over-voltage comparator eliminates output
“runaway” due to load removal
■
Low start-up current; < 0.55mA
The PFC circuits uses a new , simple PFC topology which
requires only one loop for compensation. In addition,
this PFC can be used with either peak- or average-current
mode. This system produces a power factor of better than
0.99 with low input current THD.
The ballast controller section provides for programmable
starting sequence with individual adjustable preheat and
lamp out-of-socket interrupt times. The ML4835 provides
a shut down for both PFC and ballast controllers in the
event of end-of-life for the CFL.
(* Indicates Part is End Of Life as of July 1, 2000)
BLOCK DIAGRAM
13
4
3
INTERRUPT
CRAMP
PIFBO
PIFB
PEAO
2
POWER
FACTOR
CONTROLLER
PVFB/OVP
1
7
9
8
ANTI-FLASH
COMPENSATION
AND
POWER DIMMING LEVEL
INTERFACE
10
CONTROL
AND
GATING
LOGIC
LAMP FB
5
LEAO
6
OUT A
RSET
RT/CT
RT2
17
VARIABLE FREQUENCY
OSCILLATOR
OUT B
OUTPUT
DRIVERS
THREE-FREQUENCY
CONTROL SEQUENCER
16
PFC OUT
18
PGND
15
VCO
PRE-HEAT AND
INTERRUPT TIMERS
PWDET
12
END-OF-LAMP DETECT
AND
POWER SHUTOFF
UNDER-VOLTAGE
AND
THERMAL SHUTDOWN
AGND
REF
14
20
LAMP OUT DETECT
AND
AUTOMATIC LAMP
RESTART
RX/CX
11
VCC
19
1
ML4835
PIN CONFIGURATION
ML4835
20-Pin SOIC (S20)
20-Pin DIP (P20)
PVFB/OVP
1
20
REF
PEAO
2
19
VCC
PIFB
3
18
PFC OUT
PIFBO
4
17
OUT A
LAMP FB
5
16
OUT B
LEAO
6
15
PGND
RSET
7
14
AGND
RT2
8
13
CRAMP
RT/CT
9
12
PWDET
INTERRUPT
10
11
RX/CX
PIN DESCRIPTION
PIN
NAME
FUNCTION
PIN
NAME
1
PVFB/OVP
Inverting input to the PFC error
amplifier and OVP comparator input.
10
2
PEAO
PFC error amplifier output and
compensation node
INTERRUPT Input used for lamp-out detection and
restart. A voltage less than 1V will
reset the IC and cause a restart after a
programmable interval.
11
3
PIFB
Senses the inductor current and peak
current sense point of the PFC cycle
by cycle current limit
RX/CX
Sets the timing for preheat and
interrupt.
12
PWDET
Lamp output power detection
13
CRAMP
Integrated voltage of the error
amplifier out
14
AGND
Analog ground
15
PGND
Power ground.
16
OUT B
Ballast MOSFET driver output
Output of the lamp current error
transconductance amplifier used for
lamp current loop compensation
17
OUT A
Ballast MOSFET driver output
18
PFC OUT
Power factor MOSFET driver output
19
VCC
Positive supply voltage
20
REF
Buffered output for the 7.5V reference
4
PIFBO
Output of the current sense amplifier.
Placing a capacitor to ground will
average the inductor current.
5
LAMP FB
Inverting input of the lamp error
amplifier, used to sense and regulate
lamp arc current. Also the input node
for dimmable control.
6
LEAO
7
R SET
External resistor which SETS oscillator
FMAX, and RX/CX charging current
8
RT2
Oscillator timing component to set
start frequency
9
RT/CT
Oscillator timing components
2
FUNCTION
ML4835
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings are those values beyond which
the device could be permanently damaged. Absolute
maximum ratings are stress ratings only and functional
device operation is not implied.
Supply Current (ICC) ............................................................. 65mA
Output Current, Source or Sink
(OUT A, OUT B, PFC OUT) DC ........................... 250mA
PIFB Input Voltage ............................................–3V to 2V
Maximum Forced Voltage
(PEAO, LEAO) ............................................ –0.3V to 7.7V
Maximum Forced Current
(PEAO, LEAO) ...................................................... ±20mA
Junction Temperature .............................................. 150ºC
Storage Temperature Range ...................... –65ºC to 150ºC
Lead Temperature (Soldering, 10 sec) ..................... 260ºC
Thermal Resistance (qJA)
ML4835CP .......................................................... 65ºC/W
ML4835CS .......................................................... 80ºC/W
OPERATING CONDITIONS
Temperature Range ....................................... 0°C to 85°C
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, VCC = VCCZ –0.5V, RSET = 11.8kW, RT = 15.4kW, RT2 = 67.5kW, CT = 1.5nF,
TA = Operating Temperature Range (Note 1)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
-0.3
-1.0
µA
75
105
µ
LAMP CURRENT AMPLIFIER (LAMP FB, LEAO)
Small Signal Transconductance
35
Input Bias Voltage
-0.3
W
Input Bias Current
5.0
V
0.4
V
Output Low
LAMP FB = 3V, RL = ¥
Output High
LAMP FB = 2V, RL = ¥
7.1
7.5
V
Source Current
LAMP FB = 0V, LEAO = 6V
-80
-220
µA
Sink Current
LAMP FB = 5V, LEAO = 0.3V
80
220
µA
0.2
PFC VOLTAGE FEEDBACK AMPLIFIER ( PEAO, PVFB/OVP)
Small Signal Transconductance
35
Input Bias Voltage
-0.3
-0.3
-1.0
µA
75
105
µ
W
Input Bias Current
5.0
V
0.4
V
Output Low
PVFB = 3V, RL = ¥
Output High
PVFB = 2V, RL = ¥
6.4
6.8
V
Source Current
PVFB = 0V, PEAO = 6V
-80
220
µA
Sink Current
PVFB = 5V, PEAO = 0.3V
80
220
µA
-0.9
-1.0
0.2
PFC CURRENT-LIMIT COMPARATOR (PIFB)
Current-Limit Threshold
Propagation Delay
100mV Step and 100mV Overdrive
-1.1
100
V
ns
PFC OVP COMPARATOR
OVP Threshold
2.65
2.75
2.85
V
Hysteresis
0.14
0.20
0.30
V
Propagation Delay
1.4
µs
3
ML4835
ELECTRICAL CHARACTERISTICS
SYMBOL
(Continued)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
39.2
40
40.8
kHz
OSCILLATOR
Initial Accuracy (FMIN)
TA = 25ºC
Voltage Stability (FMIN)
VCCZ – 4V < VCC < VCCZ – 0.5V
Temperature Stability (FMIN)
Total Variation (FMIN)
Line, Temperature
Initial Accuracy (START)
TA = 25ºC
0.3
%
0.3
%
39.2
49
50
40.8
kHz
51
kHz
Voltage Stability (START)
0.3
%
Temparature Stability (START)
0.3
%
Total Variation (START)
Line, Temperature
49
Ramp Valley to Peak
51
2.5
kHz
V
Initial Accuracy (Preheat)
TA = 25ºC
60.8
64
67.2
kHz
Total Variation (Preheat)
Line, Temperature
60.8
64
67.2
kHz
CT Discharge Current
VRTCT = 2.5V
6.0
7.5
9.0
mA
Output Drive Deadtime
CT = 1.5nF
0.7
us
REFERENCE BUFFER
Output Voltage
TA = 25ºC, IO = 0mA
Line Regulation
Load Regulation
7.4
7.5
7.6
V
VCCZ – 4V < VCC < VCCZ – 0.5V
10
25
mV
1mA < IO < 10mA
2
15
mV
Temperature Stability
0.4
Total Variation
Line, Load, Temperature
Long Term Stabilty
Tj=125ºC, 1000 hrs
7.35
Short Circuit Current
RSET Voltage
4
2.4
%
7.65
V
5
mV
40
mA
2.5
2.6
V
ML4835
ELECTRICAL CHARACTERISTICS
SYMBOL
(Continued)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
PREHEAT AND INTERRUPT TIMER (RX = 346kW, CX = 10µF)
Initial Preheat Period
0.86
s
Subsequenct Preheat Period
0.72
s
Interrupt Period
5.9
s
RX/CX Charging Current
-50
-54
-58
µA
RX/CX Open Circuit Voltage
0.4
0.7
1.0
V
RX/CX Maximum Voltage
7.0
7.3
7.8
V
Preheat Lower Threshold
1.6
1.75
1.9
V
Preheat Upper Threshold
4.4
4.65
4.9
V
Start Period End Threshold
6.2
6.6
6.9
V
Interrupt Disable Threshold
1.1
1.25
1.4
V
0.16
0.26
0.36
V
1
µA
1
1.1
V
IOUT = 20mA
0.1
0.2
V
IOUT = 200mA
1.0
2.0
V
Hysteresis
Input Bias Current
POWER SHUTDOWN
Power Shutdown Voltage
0.9
OUTPUTS (OUT A, OUT B, PFC OUT)
Output Voltage Low
Output Voltage High
IOUT = 20mA
VCC-0.2
VCC-0.1
V
Output Voltage High
IOUT = 200mA
VCC-2.0
VCC-1.0
V
Output Voltage Low in UVLO
IOUT = 10mA, VCC < VCC START
Output Rise and Fall Time
CL=1000pF
0.2
50
V
ns
UNDER VOLTAGE LOCKOUT AND BIAS CIRCUITS
IC Shunt Voltage (VCCZ)
ICC=15mA
Start-up Threshold (VCC START)
14.0
15.5
VCCZ-1.5 VCCZ-1.0 VCCZ-0.5
Hysteresis
3.0
V
V
3.7
4.4
V
Start-up Current
VCC START –0.2V
350
550
µA
Interrupt Current
(VCC–0.5V), INTERRUPT = 0V
500
750
µA
Operating Current
(VCC–0.5V)
5.5
8.0
mA
Shutdown Temperature
Hysteresis
Note 1:
14.8
130
ºC
30
ºC
Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions.
5
ML4835
FUNCTIONAL DESCRIPTION
The ML4835 consists of peak or average current
controlled continuous boost power factor front end section
with a flexible ballast control section. Start-up and lampout retry timing are controlled by the selection of external
timing components, allowing for control of a wide variety
of different lamp types. The ballast section controls the
lamp power using frequency modulation (FM) with
additional programmability provided to adjust the VCO
frequency range. This allows for the IC to be used with a
variety of different output networks. Figure 1 depicts a
detailed block diagram of ML4835.
• End-of-lamp life detection to detect EOL and shut-off
lamps; See End Of Life Section.
• Thermal shutdown for temperature sensing extremes;
See IC Bias, Under-Voltage Lockout and Thermal
Shutdown Section.
• Relamping starting with anti-flash for programmable
restart for lamp out conditions while minimizing
“flashing” when powering from full power to dimming
levels; See Starting, Re-Start, Preheat and Interrupt
Section
The ML4835 provides several safety features. See the
corresponding sections for more details:
REF
REF_OK
20
19
THERMAL SHUTDOWN
+
VCC
6.75V
REF
OUT A
17
–
AGND
14
+
TEMP
–
130ºC/100ºC
OUT B
16
PGND
–
Q
+
14V
PWDET
UVLO
Q
13
15
R
12
+
S
–
1.0V
CRAMP
PREHEAT
+
PVFB/OVP
1
V
–
4.75V/
1.75V
TO
+
2.5V
I
Q
S
Q
R
+
PIFBO
R
–
4
Q
Q
10
–
–
PEAO
2
1.25V/1V
INTERRUPT
+
COMP
–
RX/CX
+
6.75V/1.25V
T
S
PIFB
Q
CLK1
Q
RT2
÷2
8
3
PFC OUT
18
+
7
Q
ILIM
2.75V
+
PVFB
–
11
R
–
–1V
S
OVP
Q
6
LAMP FB
RX/CX
5
–
V TO I
RSET
9
LEAO
OSCILLATOR
PFC CONTROLLER
+
V TO I
Figure 1. Detailed Block Diagram
6
RT/CT
CLK
2.5V
ML4835
FUNCTIONAL DESCRIPTION
(Continued)
The ML4835 implements a triple frequency operation
scheme: programmable three-frequency sequence for preheat, ignition, and dimming, that extends lamp life,
simplifies lamp network design, and starts lamps at any
dimming level without flashing. This addresses the need
for a high-Q network for starting sequence and low-Q
network for operation, minimizing parasitic losses and
improving overall power efficiency. The values for the
pre-heat, start, operation, and restart can be programmed
or selected (Figure 2).
POWER FACTOR SECTION
The ML4835 power factor section is a peak or average
current sensing boost mode PFC control circuit in which
only voltage loop compensation is needed. It is simpler
than a conventional average current control method. It
consists of a voltage error amplifier, a current sense
amplifier (no compensation is needed), an integrator, a
comparator, and a logic control block. In the boost
topology, power factor correction is achieved by sensing
the output voltage and the current flowing through the
current sense resistor. Duty cycle control is achieved by
comparing the integrated voltage signal of the error
amplifier and the voltage across RSENSE. The duty cycle
control timing is shown in Figure 3.
PREHEAT
f1
SET TIME VALUES
FOR PREHEAT,
START AND OPERATION,
AND RESTART
HIGH Q
ML4835
LOW Q
f2
f3
START
OPERATION
Figure 2. Three Frequency Design Model
L
VOUT
SW2
LAMP
RA
EMI
FILTER
LAMP
NETWORK
INVERTER
3
4
PIFB
18
PIFBO
–A
RB
SW1
RSENSE
LAMP
1
PFC OUT
PVFB/OVP
+
R
Q
–
S
PIFBO
CLK
OSC
PEAO
RAMP
–
V TO I
+
VREF1
CLK
PFC OUT
CRAMP
13
PEAO
2
CRAMP
R1
C2
C1
Figure 3. ML4835 PFC Controller Section
7
ML4835
FUNCTIONAL DESCRIPTION
(Continued)
Setting minimum input voltage for output regulation can
be achieved by selecting CRAMP as follows for peak
current mode:
CRAMP =
:
?
PEAO MAX
(1 - D)Ts - Dt
22K
!
1
"#
#$
V
- 2VIN
2POUT
- OUT
(1 - D)Ts 8 ´ R SENSE
VIN
2L
(1)
OVERVOLTAGE PROTECTION AND INHIBIT
The OVP pin serves to protect the power circuit from
being subjected to excessive voltages if the load should
change suddenly (lamp removal). A divider from the high
voltage DC bus sets the OVP trip level. When the voltage
on PVFB/OVP exceeds 2.75V, the PFC transistor are
inhibited. The ballast section will continue to operate.
And for average current mode:
TRANSCONDUCTANCE AMPLIFIERS
CRAMP
:
PEAO MAX
(1 - D)Ts - Dt
=
22K
?
!
1
"#
#$
V
2POUT
- OUT (1 - D)Ts 8 ´ R SENSE
VIN
2L
(1a)
Where Dt is the dead time.
The PFC voltage feedback amplifier is implemented as an
operational transconductance amplifier. It is designed to
have low small signal forward transconductance such that
a large value of load resistor (R1) and a low value
ceramic capacitor (<1µF) can be used for AC coupling
CURRENT
MIRROR
POWER DETECT
IN
IQ +
IQ –
POWER LEVEL
TRIP POINT
ML4835
OUT
gmVIN
2
io = gmVIN
gmVIN
2
POWER SHUTOFF
IN
OUT
CURRENT
MIRROR
Figure 4. Simplified Model of ML4835 EOL Functionality
Figure 6. Output Configuration
iO
PVFB/OVP
1
–
2.5V
+
R1
C2
0
VIN DIFFERENTIAL
LINEAR SLOPE REGION
C1
Figure 5. Compensation Network
8
Figure 7. Transconductance Amplifier Characteristics
ML4835
REF
20
RT
RT2
RT2
8
DURING PREHEAT
ICHG = 2.5V
RSET
AFTER PREHEAT
LEA_ENB = HI
ICHG = 5V – 7.5V
RSET
8K±25%
LEA_ENB = LOW
ICHG = 5V – LEAO
RSET
8K±25%
ICHG
9
RT/CT
+
3.75/1.25V
–
LEA_ENB
10
+
VCC
0.625
RSET
11
5.5mA
–
1.25/1.0V
19
CT
+
INTERRUPT
RX/CX
NOTE 1: RSET SHOULD BE SELECTED SUCH THAT AFTER PREHEAT WITH LEA_ENB "HI",
ICHG MUST BE < 0.
7.5V
ICHG IS A UNI-DIRECTIONAL SOURCE CURRENT ONLY.
–
4.75/1.25V
+
CLOCK
tDIS
tCHG
VTH = 3.75V
CT
VTL = 1.25V
Figure 8. Oscillator Block Diagram and Timing
VCC VCCZ
V(ON)
V(OFF)
t
ICC
5.5mA
0.34mA
t
Figure 9. Typical VCC and ICC Waveforms when the ML4835 is Started with a Bleed Resistor from
the Rectified AC Line and Bootstrapped from an Auxiliary Winding.
9
ML4835
FUNCTIONAL DESCRIPTION
(Continued)
(C1) in the frequency compensation network. The
compensation network shown in Figure 5 will introduce a
zero and a pole at:
fZ =
1
2p R 1C1
fP =
1
2p R 1C 2
(2)
Figure 4 shows the output configuration for the
operational transconductance amplifiers.
A DC path to ground or VCC at the output of the
transconductance amplifiers will introduce an offset error.
The magnitude of the offset voltage that will appear at the
input is given by VOS = io/gm. For an io of 1µA and a gm
of 0.05 µW the input referred offset will be 20mV.
Capacitor C1 as shown in Figure 5 is used to block the
DC current to minimize the adverse effect of offsets.
Slew rate enhancement is incorporated into all of the
operational transconductance amplifiers in the ML4835.
This improves the recovery of the circuit in response to
power up and transient conditions. The response to large
signals will be somewhat non-linear as the
transconductance amplifiers change from their low to
high transconductance mode, as illustrated in Figure 7.
OSCILLATOR
The VCO frequency ranges are controlled by the output
of the LFB amplifier (RSET). As lamp current decreases,
LFB OUT falls in voltage, causing the CT charging current
to increase, thereby causing the oscillator frequency to
increase. Since the ballast output network attenuates high
frequencies, the power to the lamp will be decreased. The
oscillator frequency is determined by the following
equations:
FOSC =
1
t CHG + t DIS
and
t CHG = R T C T In
(3)
V
V
REF
REF
+ ICHG ´ R T - VTL
+ IICHG ´ R T - VTH
(4)
The oscillator’s minimum frequency is set when ICHG = 0
where:
FMIN @
1
0.51 ´ R T C T
(5)
The oscillator's start frequency can be expressed by:
END OF LAMP LIFE
At the end of a lamp’s life when the emissive material is
depleted, the arc current is rectified and high voltage
occurs across the lamp near the depleted cathode. The
ballast acts as a constant current source so power is
dissipated near the depleted cathode which can lead to
arcing and bulb cracking. Compact fluorescent lamps are
more prone to cracking or shattering because their small
diameter can’t dissipate as much heat as the larger linear
lamps. Compact fluorescents also present more of a
safety hazard since they are usually used in downlighting
systems without reflector covers.
FSTART =
2
1
7
0.51 ´ R T R T 2 ´ C T
(5a)
Both equations assume that tCHG >> tDIS.
When LFB OUT is high, ICHG = 0 and the minimum
frequency occurs. The charging current varies according
to two control inputs to the oscillator:
1. The output of the preheat timer
2. The voltage at LFB OUT (lamp feedback amplifier
output)
EOL and the ML4835
In preheat condition, charging current is fixed at
The ML4835 uses a circuit that creates a DC voltage
representative of the power supplied to the lamps through
the inverter. This voltage is used by the ML4835 to latch
off the ballast when it exceeds an internal threshold. An
external resistor can be used as the “EOL latch resistor” to
set the power level trip point, as shown in by R9 in Figure
12. See Micro Linear ML4835 User Guide and
applications notes for more details. Figure 4 illustrates a
simplified model of ML4835 EOL functionality.
BALLAST OUTPUT SECTION
The IC controls output power to the lamps via frequency
modulation with non-overlapping conduction. This means
that both ballast output drivers will be low during the
discharging time tDIS of the oscillator capacitor CT.
10
ICHG (PREHEAT ) =
25
.
R SET
(6)
In running mode, charging current decreases as the
voltage rises from 0V to VOH at the LAMP FB amplifier.
The charging current behavior can be expressed as:
ICHG =
5V
LEAO
R SET 8k ± 25%
(7)
The highest frequency is attained when ICHG is highest,
which is attained when voltage at LFB OUT is at 0V:
ICHG(0) =
5
R SET
(8)
ML4835
FUNCTIONAL DESCRIPTION
(Continued)
Highest lamp power, and lowest output frequency are
attained when voltage at LFB OUT is at its maximum
output voltage (VOH).
In this condition, the minimum operating frequency of the
ballast is set per equation 5 above.
For the IC to be used effectively in dimming ballasts with
higher Q output networks a larger CT value and lower RT
value can be used, to yield a smaller frequency excursion
over the control range (voltage at LFB OUT). The
discharge current is set to 5.5mA.
Assuming that IDIS >>IRT:
t DIS( VCO) @ 600 ´ C T
(9)
IC BIAS, UNDER-VOLTAGE LOCKOUT AND
THERMAL SHUTDOWN
The IC includes a shunt clamp which will limit the
voltage at VCC to 15V (VCCZ). The IC should be fed with
a current limited source, typically derived from the
ballast transformer auxiliary winding. When VCC is below
VCCZ – 1.1V, the IC draws less than 0.55mA of quiescent
current and the outputs are off. This allows the IC to start
using a “bleed resistor” from the rectified AC line.
To help reduce ballast cost, the ML4835 includes a
temperature sensor which will inhibit ballast operation if
the IC’s junction temperature exceeds 130°C. In order to
use this sensor in lieu of an external sensor, care should
be taken when placing the IC to ensure that it is sensing
temperature at the physically appropriate point in the
ballast. The ML4835’s die temperature can be estimated
with the following equation:
TJ @ TA + (PD + 65° C / W)
(10)
STARTING, RE-START, PREHEAT AND INTERRUPT
The circuit in Figure 10 controls the lamp starting
scenarios: Filament preheat and lamp out interrupt. CX is
charged with a current of IR(SET)/4 and discharged through
RX. The voltage at CX is initialized to 0.7V (VBE) at power
up. The time for CX to rise to 4.75V is the filament preheat
time. During that time, the oscillator charging current
(ICHG) is 2.5/RSET. This will produce a high frequency for
filament preheat, but will not produce sufficient voltage
to ignite the lamp or cause significant glow current.
After cathode heating, the inverter frequency drops to
FSTART causing a high voltage to appear to ignite the
lamp. If lamp current is not detected when the lamp is
supposed to have ignited, the CX charging current is shut
off and the inverter is inhibited until CX is discharged by
RX to the 1.25V threshold. Shutting off the inverter in this
manner prevents the inverter from generating excessive
heat when the lamp fails to strike or is out of socket.
Typically this time is set to be fairly long by choosing a
large value of RX.
LFB OUT is ignored by the oscillator until INTERRUPT is
above 1.25V The CX pin is clamped to about 7.5V.
Care should also be taken not to turn on the VCCZ clamp
so as not to dissipate excessive power in the IC. This will
cause the temp sensor to become active at a lower
ambient temperature.
A summary of the operating frequencies in the various
operating modes is shown below.
OPERATING MODE
OPERATING FREQUENCY
Preheat
[F(MAX) to F(MIN)]
2
After
Preheat
Dimming
Control
F(START)
F(MIN) to F(MAX)
The lamp starting scenario implemented in the ML4835
is designed to maximize lamp life and minimize ballast
heating during lamp out conditions.
0.625
RSET
RX/CX
+
10
RX
CX
1.25/4.75
LEA_ENB OR
DIMMING LOCKOUT
+
INTERRUPT
9
HEAT
–
1.0/1.25
–
S
+
1.25/6.75
–
Q
INHIBIT
R
Figure 10. Lamp Preheat and Interrupt Timers
11
ML4835
TYPICAL APPLICATIONS
The ML4835 can be used for a variety of lamp types:
T4 or compact fluorescent lamps
IEC T8 (linear lamps)
T5 linear lamps
T12 linear lamps
The ML4835 can also be used for dimming applications.
For example, 20:1 dimming can be achieved using the
ML4835 with external dimming units. The applications
schematics shown in Figures 12, 13, and 14 are examples
of the various uses of the ML4835.
7.5
6.75
RX/CX 4.75
1.25
.7
0
HEAT
LEA_ENB OR
DIMMING LOCKOUT
INTERRUPT
INHIBIT
Figure11. Lamp Starting and Restart Timing
12
ML4835
HOT
F1
R4, 62kΩ
L1
D1-D4: 1A, 600V
C1
3.3nF
120VRMS
D8, 1A, 600V
C3
0.15µF
D3
D1
D4
D2
6
10
9
8
D7
1A, 600V
(ULTRAFAST)
T1
L2
C2
3.3nF
D10, 0.1A
75V
NEUTRAL
D5
1A, 50V
R1
0.33Ω
R2
100Ω
D14
0.1A
75V
D11, 15V, 0.5W
2
R15, 681kΩ
3
4
5
6
7
C16
82nF
C17
8.2nF
C18
1.5nF R26
5kΩ
C4
33nF
R18
8.06kΩ
8
9
R17
4.3kΩ
10
REF
PEAO
VCC
PFC OUT
OUT A
LFB
OUT B
LEAO
P GND
RSET
A GND
RT2
RAMP
RT/CT
PW DET
INTRPT
C20
1.5nF
C19
1µF
ML4835
PIFBO
RX/CX
20
R8
180Ω
C22
1.5µF
R22
360kΩ
R5
1MΩ
R6
3.32kΩ
Q1
4
C1
100µF
R12
150Ω
Q3
2.5A, 500V
8
R9
4.3Ω
C9
1µF
R24
20kΩ
R10
30Ω
D19
1A
600V
D15
1A
600V
R
R
6
2
7
1
C11
6800pF
9
B
8
B
C14
0.015µF
C28
120pF
Y
Y
5
1
6
10
T3
D12
0.1A, 75V
C15
1µF
18
17
16
R14
22.6kΩ
R13
1kΩ
15
C26
47µF
14
13
12
11
C25
0.22µF
R23, 200kΩ
T1
3
D17, 0.1A, 75V
C30
120pF
19
C21
15µF
C24
470pF
C27
0.22µF
DIMMER INTERFACE ASSEMBLY
D1
0.1A, 75V
4
7
R8
5.76kΩ
PVFB
PIFB
T3
C12
0.33µF
3
1
R21, 51.1kΩ
C29
100pF
2
R7
432kΩ
D18
0.1A
75V
R19, 16.2kΩ
U1
C8
47µF
6
R3
820Ω
1
R11
150Ω
Q2
2.5A, 500V
3
R25
100Ω
C7
100µF
C6
0.1µF
D6
1A, 50V
Q1
4.5A, 500V
D9, 0.1A
75V
C5
0.1µF
D16, 0.1A, 75V
R6
432kΩ
R3
16.2kΩ
3
2
R4
220kΩ
5
6
C4
D2
18V 10µF
R7
3.32kΩ
D3
C2
220pF
C3, 1nF
8
+
U2A
1
R16
10kΩ
C23
6.8µF
D13
5.6V, 0.5W
R1
604Ω
R2
1.5kΩ
5
1
–
U2B
+
7
2
4
U1
–
4
C5
0.01µF
VIOLET
GREY
MANUAL DIMMER
0-10VDC
Figure12. Ballast for Architectural Dimming Applications
13
ML4835
HOT
F1
R4, 62kΩ
L1
D1-D4: 1A, 600V
C1
3.3nF
120VRMS
D8, 1A, 600V
C3
0.15µF
D3
D1
D4
D2
6
10
9
8
D7
1A, 600V
(ULTRAFAST)
T1
L2
C2
3.3nF
D10, 0.1A
75V
NEUTRAL
D5
1A, 50V
R1
0.33Ω
R2
100Ω
D14
0.1A
75V
D11, 15V, 0.5W
R7
432kΩ
D18
0.1A
75V
R8
5.76kΩ
2
R15, 681kΩ
3
4
5
6
7
C16
82nF
C17
8.2nF
C18
1.5nF R26
5kΩ
C4
33nF
R18
8.06kΩ
8
9
R17
4.3kΩ
10
REF
PEAO
VCC
PFC OUT
PIFBO
OUT A
LFB
OUT B
LEAO
P GND
RSET
A GND
RT2
RAMP
RT/CT
PW DET
INTRPT
C20
1.5nF
C19
1µF
ML4835
PIFB
RX/CX
R8
180Ω
R22
360kΩ
R5
1MΩ
R6
3.32kΩ
Q1
4
C1
100µF
C11
6800pF
10
D15
1A
600V
C14
0.015µF
C10
0.33µF
C15
1µF
17
R14
22.6kΩ
16
R13
1kΩ
15
C26
47µF
13
12
C25
0.22µF
C24
470pF
C27
0.22µF
R3
16.2kΩ
3
2
R4
220kΩ
5
6
D3
C2
220pF
C3, 1nF
8
+
U2A
1
R16
10kΩ
C23
6.8µF
D13
5.6V, 0.5W
R1
604Ω
R2
1.5kΩ
5
1
–
U2B
+
7
2
4
U1
–
4
7
1
C28
120pF
C5
0.01µF
VIOLET
GREY
MANUAL DIMMER
0-10VDC
Figure13. Ballast for Architectural Downlighting Applications
R
R
Y
Y
B
B
8
5
1
6
10
D12
0.1A, 75V
18
11
2
T3
R10
30Ω
14
6
C30
120pF
9
19
C21
15µF
C4
D2
18V 10µF
R7
3.32kΩ
14
6
R23, 200kΩ
C22
1.5µF
T1
3
3
C9
1µF
R24
20kΩ
20
DIMMER INTERFACE ASSEMBLY
D1
0.1A, 75V
R12
150Ω
Q3
2.5A, 500V
8
R9
4.3Ω
R21, 51.1kΩ
C29
100pF
D17, 0.1A, 75V
C13
2700pF T3
4
D19
1A
600V
7
1
PVFB
C12
0.33µF
8
R19, 16.2kΩ
U1
2
6
R3
820Ω
1
C8
47µF
L3
R11
150Ω
Q2
2.5A, 500V
3
R25
100Ω
C7
100µF
C6
0.1µF
D6
1A, 50V
Q1
4.5A, 500V
D9, 0.1A
75V
C5
0.1µF
D16, 0.1A, 75V
R6
432kΩ
ML4835
HOT
F1
R4, 62kΩ
L1
D1-D4: 1A, 600V
C1
3.3nF
120VRMS
D8, 1A, 600V
C3
0.15µF
D3
D1
D4
D2
6
10
9
8
D7
1A, 600V
T1
L2
C2
3.3nF
D10, 0.1A
75V
NEUTRAL
D5
1A, 50V
R1
0.33Ω
D14
0.1A
75V
D11, 15V, 0.5W
D18
0.1A
75V
2
R15, 681kΩ
C29
100pF
3
4
5
6
7
C16
82nF
C17
8.2nF
C18
1.5nF
C4
33nF
8
R26
5kΩ
9
10
R18
8.06kΩ
ML4835
REF
PEAO
VCC
PIFB
PFC OUT
PIFBO
OUT A
LFB
OUT B
LEAO
P GND
RSET
A GND
RT2
RAMP
RT/CT
PW DET
INTRPT
C20
1.5nF
T3
C12
0.33µF
4
R7
432kΩ
3
D17, 0.1A, 75V
7
R8
5.76kΩ
R21, 51.1kΩ
U1
2
1
R19, 16.2kΩ
PVFB
C8
47µF
6
R3
820Ω
1
R11
150Ω
Q2
2.5A, 500V
3
R25
100Ω
C7
100µF
C6
0.1µF
D6
1A, 50V
Q1
4.5A, 500V
D9, 0.1A
75V
C5
0.1µF
R2
100Ω
D16, 0.1A, 75V
R6
432kΩ
RX/CX
20
8
R9
4.3Ω
C9
1µF
R24
20kΩ
R10
30Ω
D19
1A
600V
R12
150Ω
Q3
2.5A, 500V
D15
1A
600V
C14
0.015µF
6
2
7
1
C11
6800pF
9
C30
120pF
C28
120pF
R
R
Y
Y
B
B
8
5
1
6
10
T3
19
18
17
16
D12
0.1A, 75V
15
C26
47µF
14
13
12
11
C25
0.22µF
R23, 200kΩ
C22
1.5µF
R22
360kΩ
C21
15µF
C24
470pF
C27
0.22µF
C23
6.8µF
R13
1kΩ
Figure14. Non-Dimming Ballast for Downlighting Applications
15
ML4835
PHYSICAL DIMENSIONS
inches (millimeters)
Package: S20
20-Pin SOIC
0.498 - 0.512
(12.65 - 13.00)
20
0.291 - 0.301 0.398 - 0.412
(7.39 - 7.65) (10.11 - 10.47)
PIN 1 ID
1
0.024 - 0.034
(0.61 - 0.86)
(4 PLACES)
0.050 BSC
(1.27 BSC)
0.095 - 0.107
(2.41 - 2.72)
0º - 8º
0.012 - 0.020
(0.30 - 0.51)
0.090 - 0.094
(2.28 - 2.39)
SEATING PLANE
0.022 - 0.042
(0.56 - 1.07)
0.005 - 0.013
(0.13 - 0.33)
0.007 - 0.015
(0.18 - 0.38)
Package: P20
20-Pin PDIP
1.010 - 1.035
(25.65 - 26.29)
20
0.240 - 0.260 0.295 - 0.325
(6.09 - 6.61) (7.49 - 8.26)
PIN 1 ID
0.060 MIN
(1.52 MIN)
(4 PLACES)
1
0.055 - 0.065
(1.40 - 1.65)
0.015 MIN
(0.38 MIN)
0.170 MAX
(4.32 MAX)
0.125 MIN
(3.18 MIN)
16
0.100 BSC
(2.54 BSC)
0.016 - 0.022
(0.40 - 0.56)
SEATING PLANE
0º - 15º
0.008 - 0.012
(0.20 - 0.31)
ML4835
PHYSICAL DIMENSIONS
inches (millimeters)
ORDERING INFORMATION
© Micro Linear 1999.
PART NUMBER
TEMPERATURE RANGE
PACKAGE
ML4835CP (End Of Life)
ML4835CS (End Of Life)
0°C to 70°C
0°C to 70°C
20-Pin DIP (P20)
20-Pin SOIC (S20)
is a registered trademark of Micro Linear Corporation. All other trademarks are the property of their respective owners.
Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502;
5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376; 5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897;
5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174; 5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669;
5,825,165; 5,825,223; 5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.
Micro Linear reserves the right to make changes to any product herein to improve reliability, function or design. Micro Linear does not assume any liability
arising out of the application or use of any product described herein, neither does it convey any license under its patent right nor the rights of others. The circuits
contained in this data sheet are offered as possible applications only. Micro Linear makes no warranties or representations as to whether the illustrated circuits
infringe any intellectual property rights of others, and will accept no responsibility or liability for use of any application herein. The customer is urged to consult
with appropriate legal counsel before deciding on a particular application.
DS4835-03
2092 Concourse Drive
San Jose, CA 95131
Tel: (408) 433-5200
Fax: (408) 432-0295
www.microlinear.com
17