ncn6004a ON Semiconductor, ncn6004a Datasheet - Page 23

• Manufacturer Part Number: ncn6004a
• Description: Dual Sam/sim Interface Integrated Circuit
• Manufacturer: ON Semiconductor

CARD_SEL
PWR_ON
PGM
When the output voltage reaches the specified value
(1.80 V or 3.0 V or 5.0 V), Q1 and Q16 are switched
OFF immediately to avoid over voltage on the output
load. In the mean time, the two extra NMOS Q2 and
Q3 are switched ON to fully discharge any current
stored into the inductor, avoiding ringing and
voltage spikes over the system. Figure 16 illustrates
the theoretical basic waveforms present in the
DC/DC converter.
CS
A0
A1
A2
A3
PWR_ON
V0
V1
Overload
VCC_OK
PWR_ON
V0
V1
Overload
VCC_OK
Vref
Vref
Figure 15. Basic DC/DC Converter Diagram
Vref_1.8/3/5 V
Vref_1.8/3/5 V
10 mF
10 mF
5.0 V
5.0 V
5.0 V
3.0 V
Voltage Regulation
Voltage Regulation
http://onsemi.com
GND
GND
NCN6004A
G_HIZ
G_HIZ
C1
C3
G_Q1
G_Q3
G_Q4
G_Q2
G_Q7
G_Q1
G_Q3
G_Q4
G_Q2
G_Q7
Q15
Q17
23
bits provided by the external mP. These controls bits are
applied to the selected DC/DC converter to generate the
programmed output voltage. The MOS drive block includes
the biases necessaries to drive the NMOS and PMOS
devices as depicted in the block diagram given Figure 15.
Vcc
Vcc
GND
GND
Q8
Q1
The control block gives the logic states according to the
Vcc
27
34
28
33
U1
U2
Vcc
Q2
Q9
22 mH
22 mH
L1
L2
GND
GND
25
36
Q10
Q3
PWR_GND
PWR_GND
CRD_VCC_A
CRD_VCC
29
32
26
35
Q11
Q16
Q4
Q18
GND
GND
Q5
Q12
Q14
Q13
Q6
Q7
GND
GND
GND
GND
R1
R2
R5
R6
10 mF
10 mF
R8
R3
R4
R7
C2
C4
GND
GND