ZL6100EVAL1Z Intersil, ZL6100EVAL1Z Datasheet - Page 20

• Manufacturer Part Number: ZL6100EVAL1Z
• Description: EVAL BOARD USB ZL6100
• Manufacturer: Intersil

Specifications of ZL6100EVAL1Z

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Where:
I
circuit
R
V
the circuit should start limiting the output current.
The ZL6100 supports “lossless” current sensing by
measuring the voltage across a resistive element that is
already present in the circuit. This eliminates additional
efficiency losses incurred by devices that must use an
additional series resistance in the circuit.
To set the current limit threshold, the user must first select a
current sensing method. The ZL6100 incorporates two
methods for current sensing, synchronous MOSFET r
sensing and inductor DC resistance (DCR) sensing;
Figure 15 shows a simplified schematic for each method.
The current sensing method can be selected using the ILIM1
pin using Table 15. The ILIM0 pin must have a finite resistor
connected to ground in order for Table 15 to be valid. If no
resistor is connected between ILIM0 and ground, the default
method is MOSFET r
method can be modified via the I
refer to Application Note AN2033 for details.
In addition to selecting the current sensing method, the
ZL6100 gives the power supply designer several choices for
NOTES:
22. 10k Ω < R
23. The number of violations allowed prior to issuing a fault response.
LIM
SENSE
LIM
ILIM0 PIN
(Note 22)
is the desired maximum current that should flow in the
R
R
R
is the voltage across the sensing element at the point
ILIM0
ILIM0
ILIM0
is the resistance of the sensing element
ILIM0
ILIM1 PIN
< 100k Ω
Resistor
OPEN
HIGH
LOW
DS(ON)
sensing. The current sensing
20
Ground-referenced, r
Blanking time: 672ns
Output-referenced, down-slope sensing (Inductor
DCR sensing) Blanking time: 352ns
Output-referenced, up-slope sensing (Inductor DCR
sensing) Blanking time: 352ns
2
C/SMBus interface. Please
CURRENT LIMITING CONFIGURATION
TABLE 15. RESISTOR SETTINGS FOR CURRENT SENSING
DS(ON)
DS(ON)
, sensing
Depends on resistor value used; see Table 16
ZL6100
the fault response during over or undercurrent condition. The
user can select the number of violations allowed before
declaring fault, a blanking time and the action taken when a
fault is detected.
FIGURE 15. CURRENT SENSING METHODS
ZL6100
ZL6100
NUMBER OF
VIOLATIONS
ALLOWED
MOSFET R
(Note 23)
(V
OUT
INDUCTOR DCR SENSING
5
5
5
MUST BE LESS THAN 4.0V)
ISENA
ISENB
ISENA
ISENB
SW
SW
GH
GH
GL
GL
DS(ON)
Best for low duty cycle and low f
Best for low duty cycle and high
f
Best for high duty cycle
V
V
SW
SENSING
IN
IN
COMMENTS
V
V
December 15, 2010
OUT
OUT
FN6876.2
SW