XC9519 TOREX [Torex Semiconductor], XC9519 Datasheet - Page 12

• Manufacturer Part Number: XC9519
• Description: Dual Output Step-Up/Inverting DC/DC Converter
• Manufacturer: TOREX [Torex Semiconductor]

■OPERATIONAL EXPLANATION (Continued)
<Current Limit>
The current limiter circuit of the XC9519 series monitors the current flowing through the driver transistor, and features a combination of the
current limit mode and the operation suspension mode.
① When the driver current is greater than a specific level, the current limit function operates to turn off the pulses from the LXP (LXN) pin at any
② When the driver transistor is turned off, the limiter circuit is then released from the current limit detection state.
③ At the next pulse, the driver transistor is turned on. However, the transistor is immediately turned off in the case of an over current state.
④ When the over current state is eliminated, the IC resumes its normal operation.
and the above three steps are repeatedly performed, the IC performs the function of integral latching the OFF state of the driver transistor, and
goes into operation suspension mode.
must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode. Depending on the state of the PC Board,
latch time may become longer and latch operation may not work. In order to avoid the effect of noise, the board should be laid out so that input
capacitors are placed as close to the IC as possible.
(a) Step-up DC/DC Converter
(b) Inverting DC/DC Converter
<Short-Circuit Protection>
and when the FBP voltage decreases less than short protection threshold voltage or FBN pin voltage becomes larger than short protection
threshold voltage and a current more than the I
the driver transistor.
12/38
The IC waits for the over current state to end by repeating the steps ① through ③. If an over current state continues for the integral latch time
Once the IC is in suspension mode, operations can be resumed by either turning the IC off via the ENP (ENN) pin, or by restoring power. Care
The short-circuit protection circuit monitors the output voltage from the V
Once the IC is in suspension mode, operations can be resumed by either turning the IC off via the ENP (ENN) pin, or by restoring power.
V
V
I
I
V
ENP
V
ENN
given timing.
OUTP
OUTN
OUTP
OUTN
LXP
LXN
XC9519
Series
Limit < 2.0ms(TYP.)
Limit < 2.0ms(TYP.)
LIM
flows to the driver transistor, the short-circuit protection quickly operates to turn off and to latch
Limit > 2.0ms(TYP.)
Limit > 2.0ms(TYP.)
OUTP
(V
OUTN
). In case where output is accidentally shorted to the GND
Current Limit Level
Current Limit Level
Restart
Restart
AGND,PGND
AGND,PGND
AGND,PGND
AGND,PGND
0mA
0mA