E-L6919ETR STMicroelectronics, E-L6919ETR Datasheet - Page 18

• Manufacturer Part Number: E-L6919ETR
• Description: IC CTRLR 5BIT PROG 2PHASE 28SOIC
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of E-L6919ETR

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.8 ~ 1.55 V
• Current - Output: 2A
• Frequency - Switching: 150kHz
• Voltage - Input: 5 ~ 12 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Power - Output: 2W
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 6.5 V
• Maximum Operating Temperature: 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-4592-2

L6919E
Figure 12. Inductor ripple current vs V
MAIN CONTROL LOOP
The control loop is composed by the Current Sharing control loop and the Average Current Mode control loop.
Each loop gives, with a proper gain, the correction to the PWM in order to minimize the error in its regulation:
the Current Sharing control loop equalize the currents in the inductors while the Average Current Mode control
loop fixes the output voltage equal to the reference programmed by VID. Figure 13 reports the block diagram of
the main control loop.
Figure 13. Main Control Loop Diagram
Current Sharing (CS) Control Loop
Active current sharing is implemented using the information from Tran conductance differential amplifier in an
average current mode control scheme. A current reference equal to the average of the read current (I
18/33
ternally built; the error between the read current and this reference is converted to a voltage with a proper gain
and it is used to adjust the duty cycle whose dominant value is set by the error amplifier at COMP pin (See fig. 14).
The current sharing control is a high bandwidth control loop allowing current sharing even during load transients.
The current sharing error is affected by the choice of external components; choose precise Rg resistor (±1% is
D02IN1392
+
+
4/5
COMP
AMPLIFIER
PWM1
PWM2
ERROR
1/5
1/5
9
8
7
6
5
4
3
2
1
0
0.5
OUT
Z
F(S)
+
-
CORRECTION
Output Voltage [V]
DUTY CYCLE
1.5
CURRENT
SHARING
PROGRAMMED
REFERENCE
BY VID
L=1.5 H, Vin=12V
FB
2.5
L=3 H, Vin=5V
R
FB
I
I
INFO2
INFO1
L 1
L 2
L=2 H,
Vin=12V
L=3 H,
Vin=12V
3.5
L=1.5 H,
Vin=5V
L=2 H,
Vin=5V
C
O
R
O
AVG
) is in-