Supertex inc.
Supertex inc.
 www.supertex.com
Doc.# DSDB-HV9918DB1
A032913
HV9918DB1
High Current LED Driver Demoboard
Specications
The HV9918DB1 demoboard is a high current LED driver designed 
to drive one or two LEDs at 700mA from a 9.0 - 16VDC input. The 
demoboard  uses  Supertex’s  HV9918  hysteretic  buck  LED  driver 
IC.
The  HV9918DB1 includes digital  control of PWM  dimming,  which 
allows the user to dim the LEDs using an external, TTL-compatible 
square wave source applied between   and  . In this case, DIM GND
the PWM dimming frequency and duty ratio are set by the external 
square wave source.
The  demoboard  is  protected  against  short  circuit  and  open  LED 
conditions. It also includes thermal derating of the LED current us-
ing an external NTC resistor to prevent over-heating.
The bottom of the HV9918DB1 is an exposed copper plane (con-
nected to the input ground) which can be connected to a 1” square 
heatsink  (eg:  374324B00035G  from  Aavid  Thermalloy)  to  allow 
for  operation  in  higher  ambient  temperatures  without  tripping  the 
HV9918’s built-in over temperature protection.
Parameter Value
Input voltage 9.0 - 16VDC
Output voltage  2.0 - 7.0V
Output current 700mA ± 5%
Line and load regulation < ±2%
Output current ripple  5% (peak to peak)
Full load efciency 
(@12.0V input) 87%
Open LED protection Yes
Output short circuit protection Yes
Dimensions 25.4mm X 29.2mm
General Description
Connection Diagram
Input Connection:  Connect the input DC voltage between 
VIN GND and   terminals.
Output Connection:  Connect  the LED(s)  between LED+ 
(anode of LED string) and   (cathode of LED string) ter-LED-
minals.
PWM Dimming Connection:
1.   If no PWM dimming is required, short PWMD and    
 VDD terminals.                                                                           
2.  If dimming using an external PWM dimming source,  
  connect the PWM source between the PWMD and  
   GND terminals.
 
NTC Thermistor Connection:
1.  If no thermal derating is required, the   terminal   NTC
  can be left open.
2.  If thermal derating of the LED current is required, the  
  NTC thermistor can be connected between    NTC
  and GND terminals as shown.
Connections
Silk Screen
NTC
+
-
Supertex