HVLED805TR STMicroelectronics, HVLED805TR Datasheet - Page 14

• 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

Application information
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Most of this current will charge the bypass capacitor connected between the Vcc pin and
ground and make its voltage rise linearly.
As the Vcc voltage reaches the start-up threshold (13 V typ.) the chip starts operating, the
internal power MOSFET is enabled to switch and the HV generator is cut off by the Vcc_OK
signal asserted high. The IC is powered by the energy stored in the Vcc capacitor.
The chip is able to power itself directly from the rectified mains: when the voltage on the V
pin falls below Vcc
generator is turned on and charges the supply capacitor until it reaches the V
threshold.
In this way, the self-supply circuit develops a voltage high enough to sustain the operation of
the device. This feature is useful especially during CC regulation, when the flyback voltage
generated by the auxiliary winding alone may not be able to keep Vcc above V
At converter power-down the system will lose regulation as soon as the input voltage falls
below V
voltage decay at system power-down.
Figure 11. Timing diagram: normal power-up and power-down sequences
DRAIN
DRAIN
Vcc
Vcc
V
V
I
I
5.5 mA
5.5 mA
Vcc
Vcc
charge
charge
Vcc
Vcc
Start
Start
restart
restart
Vin
Vin
ON
ON
Start
. This prevents converter’s restart attempts and ensures monotonic output
Power-on
Power-on
restart
(10.5V typ.), during each MOSFET’s off-time the HV current
Doc ID 18077 Rev 1
Normal operation
Normal operation
CV mode
CV mode
Normal operation
Normal operation
CC mode
CC mode
Power-off
Power-off
CCOn
CCrestart
HVLED805
.
t
t
t
t
t t
t
t t
t
t
t
CC