ZXSC310EV Diodes Zetex, ZXSC310EV Datasheet - Page 5

• Manufacturer Part Number: ZXSC310EV
• Description: BOARD EVALUATION FOR ZXSC310E5TA
• Manufacturer: Diodes Zetex

Specifications of ZXSC310EV

• Outputs And Type: 1, Non-Isolated
• Features: Programmable output current
• Voltage - Input: 0.8 ~ 8 V
• Utilized Ic / Part: ZXSC310
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

DEVICE DESCRIPTION
The ZXSC310 is PFM, controller IC which, when
combined with a high performance external transistor,
enables the production of a high efficiency boost
converter for LED driving applications. A block diagram
is shown for the ZXSC310 below.
The on chip comparator forces the driver circuit and
therefore the external switching transistor off if the
voltage at I
circuit and divider set this threshold.
The voltage at I
resistor connected in series with the emitter of the
switching transistor. A monostable following the
output of the comparator forces the turn-off time of the
output stage to be typically 1.7us. This ensures that
there is sufficient time to discharge the inductor coil
before the next on period.
ISSUE 3 - SEPTEMBER 2007
ZXSC310 Block Diagram
SENSE
SENSE
exceeds 19mV. An internal reference
is taken from a current sense
V
RE
G
V
ND
CC
I
2
R1
R2
5
With every on pulse the switching transistor is kept on
until the voltage across the current-sense resistor
exceeds the threshold of the I
length, and therefore the switching frequency, is
determined by the programmed peak current, the input
voltage and the input to output voltage differential. See
applications section for details.
The driver circuit supplies the external switching
transistor with a fixed drive current. To maximise
efficiency the external transistor switched quickly,
typically being forced off within 30ns.
Drive
I
V
S
I
SENSE
DRIVE
SENSE
TDN
S E M I C O N D U C T O R S
input. The on-pulse
ZXSC310