InnoSwitch3-CE
Pin Functional Description
ISENSE (IS) Pin (Pin 1)
Connection to the power supply output terminals. An external
current sense resistor should be connected between this and the
GND pin. If current regulation is not required, this pin should be tied
to the GND pin.
ꢀ ꢁ3
ꢄꢅꢅ ꢁꢆ
ꢃC ꢁꢇ
ꢁꢂ ꢃC
ꢁꢁ ꢃC
ꢁꢈ ꢃC
ꢉ ꢃC
SECONDARY GROUND (GND) (Pin 2)
ꢌ ꢃC
GND for the secondary IC. Note this is not the power supply output
GND due to the presence of the sense resistor between this and the
ISENSE pin.
S ꢁꢊ-ꢁꢉ
ꢍ ꢎꢏꢋ
ꢊ ꢀꢐꢑꢒ
ꢇ Sꢓ
ꢆ ꢄꢅS
3 ꢎꢄ
FEEDBACK (FB) Pin (Pin 3)
Connection to an external resistor divider to set the power supply
output voltage.
ꢂ ꢔꢃꢋ
ꢁ IS
ꢋ ꢂꢆ
SECONDARY BYPASS (BPS) Pin (Pin 4)
Connection point for an external bypass capacitor for the secondary
IC supply.
ꢀꢁꢂꢃ8ꢃꢃꢂ0ꢄꢄꢄ1ꢅ
SYNCHRONOUS RECTIFIER DRIVE (SR) Pin (Pin 5)
Gate driver for external SR FET. If no SR FET is used connect this pin
to GND.
Figure 5. Pin Configuration.
OUTPUT VOLTAGE (VOUT) Pin (Pin 6)
Connected directly to the output voltage, to provide current for the
controller on the secondary-side and provide secondary protection.
InnoSwitch3-CE Functional Description
The InnoSwitch3-CE combines a high-voltage power MOSFET switch,
along with both primary-side and secondary-side controllers in one
device.
FORWARD (FWD) Pin (Pin 7)
The connection point to the switching node of the transformer output
winding providing information on primary switch timing. Provides power
for the secondary-side controller when VOUT is below threshold.
The architecture incorporates a novel inductive coupling feedback
scheme (FluxLink) using the package lead frame and bond wires to
provide a safe, reliable, and cost-effective means to transmit
accurate, output voltage and current information from the secondary
controller to the primary controller.
NC Pin (Pin 8-12)
Leave open. Should not be connected to any other pins.
UNDER/OVER INPUT VOLTAGE (V) Pin (Pin 13)
A high-voltage pin connected to the AC or DC side of the input bridge
for detecting undervoltage and overvoltage conditions at the power
supply input. This pin should be tied to SOURCE pin to disable UV/OV
protection.
The primary controller on InnoSwitch3-CE is a Quasi-Resonant (QR)
flyback controller that has the ability to operate in continuous
conduction mode (CCM), boundary mode (CrM) and discontinuous
conduction mode (DCM). The controller uses both variable frequency
and variable current control schemes. The primary controller consists
of a frequency jitter oscillator, a receiver circuit magnetically coupled to
the secondary controller, a current limit controller, 5 V regulator on
the PRIMARY BYPASS pin, audible noise reduction engine for light
load operation, bypass overvoltage detection circuit, a lossless input
line sensing circuit, current limit selection circuitry, over-temperature
protection, leading edge blanking, secondary output diode / SR FET
short protection circuit and a 650 V power MOSFET.
PRIMARY BYPASS (BPP) Pin (Pin 14)
The connection point for an external bypass capacitor for the
primary-side supply. This is also the ILIM selection pin for choosing
standard ILIM or ILIM+1.
NC Pin (Pin 15)
Leave open. Should not be connected to any other pins.
SOURCE (S) Pin (Pin 16-19)
These pins are the power MOSFET source connection. Also ground
reference for primary BYPASS pin.
The InnoSwitch3-CE secondary controller consists of a transmitter
circuit that is magnetically coupled to the primary receiver, a constant
voltage (CV) and a constant current (CC) control circuit, a 4.4 V
regulator on the SECONDARY BYPASS pin, synchronous rectifier FET
driver, QR mode circuit, oscillator and timing circuit, and numerous
integrated protection features.
DRAIN (D) Pin (Pin 24)
Power MOSFET drain connection.
Figure 3 and Figure 4 show the functional block diagrams of the
primary and secondary controller, highlighting the most important
features.
3
Rev. D 08/18
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