L6520, L6521 Electrical characteristics
Doc ID 16998 Rev 3 7/19
V
OH
HSD LSD Output high voltage Iload = 300 mA 13 V
I
SRC
HSD LSD Peak source current 300 mA
I
SNK
HSD LSD Peak sink current 300 mA
T
RISE
HSD LSD Rise time Cload = 1 nF 120 ns
T
FALL
HSD LSD Fall time Cload = 1 nF 120 ns
I
PD
HSD LSD Pull down current
Before turn-on, (V
CC
= 13V)
V
LSD
or V
HSD
= 1V
20 mA
Storage time compensation and hard switching detection
V
OUTup
PWM_det PWM detector threshold Positive going HB middle point 2.65 3 V
V
HSW
PWM_det
Hard switching detector
threshold
Negative going HB middle point 2 2.35 V
V
P_dclamp
PWM_det Clamping voltage I
PWM_det
= 2 mA 4.5 5 5.5 V
t
HSW
PWM_det
Max. time of hard switching
operation
(4)
, T
AMB
= 25 °C 200 ms
Half bridge current control circuit (CCC)
THL HBCS
First threshold in ignition
mode
0.96 1 1.04 V
THM HBCS
Second threshold in ignition
mode
1.21 1.26 1.31 V
THH HBCS
Third threshold in ignition
mode
2.4 2.5 2.6 V
TLL HBCS First threshold in run mode 0.67 0.7 0.73 V
TLM HBCS Second threshold in run mode 0.87 0.9 0.93 V
TLH HBCS Third threshold in run mode 1.7 1.8 1.9 V
T
PROT
Maximum current control time
(4)
, T
AMB
= 25 °C 200 ms
t1 HBCS
Minimum interval between two
consecutive threshold
crossing for slow events
(4)
, T
AMB
= 25 °C 510 ns
t2 HBCS
Minimum interval between two
consecutive threshold
crossing for fast events (not
saturating)
(4)
, T
AMB
= 25 °C 255 ns
f
TxL
HBCS
Frequency increase in case of
lower threshold crossing
(4)
, T
AMB
= 25 °C 1 kHz
f
slow
HBCS
Frequency increase in case of
slow event
(4)
, T
AMB
= 25 °C 1 kHz
f
fast
HBCS
Frequency increase in case of
fast event
(4)
, T
AMB
= 25 °C 2 kHz
Table 5. Electrical characteristics (continued)
Symbol Pin Parameter Test condition Min. Typ. Max. Unit
Electrical characteristics L6520, L6521
8/19 Doc ID 16998 Rev 3
t
LEB
HBCS
Leading edge time after LSD
turn on
(4)
, T
AMB
= 25 °C 255 ns
End of life
V
EOL
EOL
EOL pin biasing voltage
reference
2.43 2.5 2.57 V
V
EOL_H
EOL EOL upper threshold 3.84 4 4.16 V
V
EOL_l
EOL EOL lower threshold 0.96 1 1.04 V
I
EOL
EOL Sink/source capability
V
EOL
= 1.5V (source)
V
EOL
= 3.5V (sink)
8.2 9.1 10 µA
t
EOL
EOL Protection delay time
(4)
, T
AMB
= 25 °C 1.5 s
1. During the operation at Vcc Vz the maximum supply current must be limited to 2mA.
2. Guaranteed by characterization.
3. t
DEAD
is the sum of a fixed time, generated by internal logic and the propagation delay of PWM_det comparator.
4. Guaranteed by testing logic verification.
Table 5. Electrical characteristics (continued)
Symbol Pin Parameter Test condition Min. Typ. Max. Unit
L6520, L6521 Functions description
Doc ID 16998 Rev 3 9/19
5 Functions description
5.1 Start-up
During the first start-up ramp of the supply voltage (V
CC
) both driver outputs, LSD and HSD,
are low impedance to ground (Isink 20 mA min). Once the V
CC
voltage reaches the turn-on
voltage V
CC(ON)
the IC starts its operation. During the first 100 µs the IC senses the status
of FPRE pin to detect the programmed preheating frequency and the selected ignition mode
(instant or preheated start). When all the IC internal functions are ready, the driver-outputs
are released.
If the preheated start is selected, the half-bridge oscillates at the programmed preheating
frequency, otherwise it starts from 85 kHz (typ.).
5.2 Preheating and instant start
The preheating time is 1.5 s (typ.) in the L6520 and 0.8 s (typ.) in the L6521. The FPRE pin
embeds a precise current reference: the voltage read by this pin sets the preheating
frequency or enables the instant start. If the FPRE pin is connected to ground, the instant
start is active and the IC runs immediately into ignition sequence from the starting frequency
of 85 kHz. If the pin FPRE is connected to a resistor equal or higher than 196 , the
preheating frequency can be programmed from 55 kHz upwards till 100 kHz (1.5 kHz/step)
accordingly to Table 6. For the best precision the resistor tolerance should be less or equal
to 1%. After the preheating sequence, the IC runs into ignition mode.
Table 6. Preheating and instant start
F
PRE
(kHz) R
FPRE
() F
PRE
(kHz) R
FPRE
()
Instant start 0 77.5 5490
55 196 79 6190
56.5 383 80.5 6980
58 576 82 7870
59.5 806 83.5 8660
61 1050 85 9530
62.5 1300 86.5 10500
64. 1580 88 11500
65.5 1870 89.5 12700
67 2210 91 14000
68.5 2550 92.5 15400
70 2940 94 16900
71.5 3400 95.5 18700
73 3830 97 20500
74.5 4320 98.5 22600
76 4870 100 24900

L6521

Mfr. #:
Manufacturer:
STMicroelectronics
Description:
Display Drivers & Controllers LV Smart Ballast CTR Half Bridge BJT FET
Lifecycle:
New from this manufacturer.
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