HVLED805TR STMicroelectronics, HVLED805TR Datasheet - Page 23

• Manufacturer Part Number: HVLED805TR
• Description: IC LED DRVR ACDC OFFLINE 16NSOIC
• Manufacturer: STMicroelectronics
• Type: General Purposer

Specifications of HVLED805TR

• Constant Current: Yes
• Constant Voltage: Yes
• Topology: AC DC Offline Switcher, PWM
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: General Purpose
• Voltage - Supply: 11.5 V ~ 23 V
• Mounting Type: Surface Mount
• Package / Case: *
• Internal Switch(s): Yes
• Efficiency: *
• Operating Supply Voltage: 11.5 V to 23 V
• Maximum Supply Current: 1.4 mA
• Maximum Power Dissipation: 0.9 W
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Frequency: -
• Operating Temperature: -
• Current - Output / Channel: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-10810-2

HVLED805
5.8
5.9
Figure 18. Load-dependent operating modes: timing diagrams
Soft-start and starter block
The soft start feature is automatically implemented by the constant current block, as the
primary peak current will be limited from the voltage on the C
During start-up, as the output voltage is zero, the IC will start in CC mode with no high peak
current operations. In this way the voltage on the output capacitor will increase slowly and
the soft-start feature will be ensured.
Actually the C
on others circuit parameters, like transformer ratio, sense resistor, output capacitors and
load. The user will define the best appropriate value by experiments.
Hiccup mode OCP
The device is also protected against short circuit of the secondary rectifier, short circuit on
the secondary winding or a hard-saturated flyback transformer. A comparator monitors
continuously the voltage on the R
exceeds 1 V.
To distinguish an actual malfunction from a disturbance (e.g. induced during ESD tests), the
first time the comparator is tripped the protection circuit enters a “warning state”. If in the
subsequent switching cycle the comparator is not tripped, a temporary disturbance is
assumed and the protection logic will be reset in its idle state; if the comparator will be
tripped again a real malfunction is assumed and the device will be stopped.
This condition is latched as long as the device is supplied. While it is disabled, however, no
energy is coming from the self-supply circuit; hence the voltage on the V
decay and cross the UVLO threshold after some time, which clears the latch. The internal
start-up generator is still off, then the V
COMP
V
COMPL
I
DS
Normal-mode
LED
value is not important to define the soft-start time, as its duration depends
T
Doc ID 18077 Rev 1
START
SENSE
CC
and activates a protection circuitry if this voltage
T
START
voltage still needs to go below its restart voltage
Burst-mode
T
START
LED
T
capacitor.
START
Application information
CC
Normal-mode
capacitor will
hyster.
65 mV
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