ZXLD1370EST16TC Diodes Zetex, ZXLD1370EST16TC Datasheet - Page 29

• Manufacturer Part Number: ZXLD1370EST16TC
• Description: IC LED DRVR HIGH BRIGHT TSSOP-16
• Manufacturer: Diodes Zetex
• Type: HBLED Driverr

Specifications of ZXLD1370EST16TC

• Constant Current: *
• Constant Voltage: *
• Topology: *
• Number Of Outputs: *
• Internal Driver: *
• Type - Primary: *
• Type - Secondary: *
• Frequency: *
• Voltage - Supply: *
• Voltage - Output: *
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Operating Temperature: *
• Current - Output / Channel: *
• Internal Switch(s): No
• Efficiency: 95%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ZXLD1370EST16TCTR

ZXLD1370
Document number: DS32165 Rev. 4 - 2
Applications Information
Over-voltage Protection
The ZXLD1370 is inherently protected against open-circuit load when used in Buck configuration. However care has to be
taken with open-circuit load conditions in Buck-Boost or Boost configurations. This is because in these configurations there
is no internal open-circuit protection mechanism for the external MOSFET. In this case an Over-Voltage-Protection (OVP)
network should be provided externally to the MOSFET to avoid damage due to open circuit conditions. This is shown in
figure 38 below, highlighted in the dotted blue box.
The zener voltage is determined according to: Vz = V
If the LEDA voltage exceeds V
off Q1 until the voltage on the drain of Q1 falls below Vz. If the voltage at LEDA remains above V
the ZXLD1370 will enter into a shutdown state.
Care should be taken such that the maximum gate voltage of the Q2 MOSFET is not exceeded.
Take care of the max voltage drop on the Q2 MOSFET gate.
Z
the gate of MOSFET Q2 will rise turning Q2 on. This will pull the PWM pin low and switch
(Continued)
Figure 38. OVP circuit
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+10% where V
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Diodes Incorporated
A Product Line of
is maximum LED chain voltage.
Z
for longer than 20ms then
© Diodes Incorporated
ZXLD1370
March 2011