Pin description, Cs1680 – Cirrus Logic CS1680 User Manual
Page 3
CS1680
DS1055F1
3
2. PIN DESCRIPTION
Pin Name
Pin #
I/O
Description
CTRL2
1
IN
Peak Current — Connect a resistor to this pin to set
the comparator threshold to
reflect the desired boost peak current in Trailing Edge Electronic Trans-
former Mode (Mode 2).
eOTP
2
IN
External Overtemperature Protection — Connect an external NTC thermistor to
this pin, allowing the internal A/D converter to sample the change to NTC resistance.
BSTSENSE
3
IN
Boost Stage Current Sense — The current flowing in the boost stage FET is
sensed across a resistor. The resulting voltage is applied to this pin and digitized for
use by the boost stage computational logic to determine the FET duty cycle.
GND
4
PWR
Ground — Common reference. Current return for both the input signal portion of the
IC and the gate driver.
BSTGD
5
OUT
Boost Gate Driver — Gate drive for the boost stage power FET.
VDD
6
PWR
IC Supply Voltage — Connect a storage capacitor to this pin to serve as a reservoir for
operating current for the device, including the gate drive current to the power transistor.
GPIO
7
IN/OUT
General Purpose Input/Output — Used to drive the FET gate for the startup circuit.
NC
8
IN
No Connect — Leave pin not connected.
BUCKZCD
9
IN
Buck Stage Zero-current Detect — Buck stage inductor sensing input. The pin is
connected to the drain of the buck stage power FET with a capacitor.
NC
10
IN
No Connect — Leave pin not connected.
CLAMP
11
OUT
Voltage Clamp Current Source — Connect to a voltage clamp circuit on the output
of the boost stage.
BUCKGD
12
OUT
Buck Gate Driver — Gate drive for the buck stage power FET.
BUCKSENSE
13
IN
Buck Stage Current Sense — The current flowing in the buck stage FET is sensed
across a resistor. The resulting voltage is applied to this pin and digitized for use by
the buck stage computational logic to determine the FET duty cycle.
VAC
14
IN
Rectifier Voltage Sense — A current proportional to the rectified line voltage is fed
into this pin. The current is measured with an A/D converter.
BSTOUT
15
IN
Boost Output Voltage Sense — A current proportional to the boost output is fed
into this pin. The current is measured with an A/D converter.
CTRL1
16
IN
Boost Stage Constant — Connect a resistor to this pin to set the constant ratio for
the boost stage current calculations in Leading Edge Electronic Transformer Mode
(Mode 3).
General Purpose Input/Output
Boost Gate Driver
Ground
Peak Current
External Overtemperature Protection
No Connect
GPIO
VDD
IC Supply Voltage
BSTGD
GND
CTRL2
NC
CLAMP
BUCKGD
BUCKSENSE
VAC
BSTOUT
CTRL1
eOTP
BSTSENSE
Boost Stage Current Sense
16-lead TSSOP
NC
BUCKZCD
7
6
5
4
3
2
1
10
11
12
13
14
15
16
8
9
No Connect
Voltage Clamp Current Source
Buck Gate Driver
Buck Stage Current Sense
Rectifier Voltage Sense
Boost Output Voltage Sense
Boost Stage Constant
Buck Stage Zero-current Detect
Figure 2. CS1680 Pin Assignments