IR21593SPBF International Rectifier, IR21593SPBF Datasheet - Page 15

• Manufacturer Part Number: IR21593SPBF
• Description: IC BALLAST CONTROL DIM 16-SOIC
• Manufacturer: International Rectifier
• Type: Ballast Controllerr

Specifications of IR21593SPBF

• Frequency: 30 ~ 230 kHz
• Current - Supply: 10mA
• Voltage - Supply: 12.5 V ~ 15.6 V
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Lead Free Status / Rohs Status: RoHS Compliant part

Under-voltage Lock-Out (UVLO)
The IR21592/IR21593 undervoltage lock-out is
designed to maintain an ultra low quiescent
current of less than 200uA, while guaranteeing
the IC is fully functional before the high and low
side output drivers are activated. Figure 5 shows
an efficient supply voltage using the start-up
current of the IR21592/IR21593 together with a
charge pump from the ballast output stage (R1,
C1, C2, D1 and D2).
www.irf.com
Rectified
AC Line
V
V
BUS
BUS
CVDC
Figure 4, Lamp power vs. phase of output stage.
-60.0
-65.0
-70.0
-75.0
-80.0
-85.0
-90.0
(+)
(-)
Figure 5, Typical application of start-up circuitry.
0
R3
VDC
RVDC
5
1
10
Lamp Pow er [Watts]
16
15
14
13
12
11 LO
COM
VCC
HO
VS
VB
15
C3
D3
R1
C1
20
D1
Q1
Q2
25
RCS
Half-Bridge
Output
C2
D2
30
IR21592/IR21593
The start-up capacitor (C1) is charged by current
through resistor (R1) minus the start-up current
drawn by the IC. This resistor is typically chosen
to provide 2X the maximum start-up current at
low line to guarantee start-up under the worst case
condition. Once the capacitor voltage reaches the
start-up threshold, and, the voltage on pin VDC is
above 5.1V (see Brown-out Protection), the IC
turns on and HO and LO begin to oscillate. The
capacitor begins to discharge due to the increase
in IC operating current (Figure 6).
During the discharge cycle, the rectified current
from the charge pump charges the capacitor above
the minimum operating voltage of the device and
the charge pump and internal 15.6V zener clamp
of the IC take over as the supply voltage. The
start-up capacitor and snubber capacitor must be
selected such that worst case IC conditions are
satisfied. A bootstrap diode (D3) and supply
capacitor (C3) comprise the supply voltage for
the high side driver circuitry. To guarantee that
the high-side supply is charged up before the first
pulse on pin HO, the first pulse from the output
drivers comes from the LO pin. During UVLO,
the high and low side driver outputs are low, pin
VCO is pulled-up internally to 5V resetting the
starting frequency to the maximum, and pin CPH
is short-circuited internally to COM resetting the
preheat time.
V
C1
R1 & C1 TIME
CONSTANT
V
Figure 6, Start-up capacitor (C1) voltage.
V
UVLO+
UVLO-
VHYST
DISCHARGE
C1
CHARGE PUMP
OUTPUT
DISCHARGE
TIME
( S ) & ( PbF )
INTERNAL
CLAMP VOLTAGE
t
15