The document details the device modeling report for the NJM2374A PWM DC/DC converter IC, including circuit simulations and evaluations for various configurations such as step-down, step-up, and inverting converters. It features circuit diagrams, reference voltages, and simulation results that illustrate performance characteristics like saturation voltage versus collector current. All content is copyright protected by Bee Technologies Inc. in 2006.

1. Device Modeling Report
COMPONENTS: PWM DC/DC CONVERTER IC
PART NUMBER: NJM2374A
MANUFACTURER: NEW JAPAN RADIO
Bee Technologies Inc.
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

2. PWM comparator diagram (High Voltage Detect)
Circuit Simulation Result
Reference
Voltage
VIN+
V(U1:IN+) V(X_U1.REF)
Oscillator
WaveformE L > >
S
V(U1:CT)
X_U1.LT
FF Reset
Collector-Emitter
Voltage
VC(X_U1.Q_QC)- VE(X_U1.Q_QC)
Time
Evaluation circuit
Rsc 0.22 L1
V+
180uH
RC
180 U1 D1
Vcc CD CS
VOUT
SI ES
5Vdc V+ CT DCON
IN+ GND 1
8.2k R2 NJM2374A CT RL
1500p 250
R1 Cout
953 150u
IC = 11
0
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

3. PWM comparator diagram (Current-Limit Active Point)
Circuit Simulation Result
Reference
Voltage
VIN+ Current-Limit
Active Point
V(U1:IN+) V(X_U1.REF)
Oscillator
Waveform
V(U1:CT)
FF Reset
X_U1.LT 1
Collector-Emitter
X_U1.FFS 1
Voltage
SEL>>
Time
Evaluation circuit
Rsc L1
V+
180uH
0.22 RC
180 U2 D1
Vcc CD CS
VOUT
SI ES
5Vdc V+ CT DCON VIL
IN+ GND 1 0
E1
8.2k R2 NJM2374A CT CTL
1500p OUT+ IN+
R1 Cout OUT- IN- T1 = 0
953 150u EVALUE
IC = 11 V(L1)*(V(CTL)-1) T2 = 5m V2
L1 R4
T3 = 5.05m
RLST 1MEG
0 T4 = 5.09m
250
V1 = 1
V2 = 1
0 V3 = 0.05
V4 = 1
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

4. Saturation Voltage 1 vs. collector Current
Circuit Simulation Result
2.0V
1.5V
1.0V
0.5V
0V
0A 0.5A 1.0A 1.5A 2.0A
V(Q2:c)
I(VIC)
Evaluation circuit
VIC
Q1
QC
Q2
QSW 14*I(VB)
VB R1 GVALUE
160
OUT- IN-
OUT+ IN+
GVC
I1
0.05Adc
0 0 0
*REMARK: Simulation use transistor inside .subckt model of NJM2374A
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

5. Saturation Voltage 2 vs. collector Current
Circuit Simulation Result
2.0V
1.5V
1.0V
0.5V
0V
0A 0.5A 1.0A 1.5A 2.0A
V(Q1:c)
IC(Q1)
Evaluation circuit
Q1
QC 14*I(VB)
GVALUE
VB
OUT- IN-
OUT+ IN+
GVC
I1
0.05Adc
0 0
0
*REMARK: Simulation use transistor inside .subckt model of NJM2374A
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

6. Step-Down Converter Reference
Circuit Simulation Result
15V 30V
1 2
VIN=25V
10V 20V
VOUT=5V
5V 10V
>>
0V 0V
0s 0.5ms 1.5ms 2.5ms 3.5ms 4.5ms
1 V(VOUT) 2 V(Vcc:+)
Time
Evaluation circuit
Rsc
V+
U1
0.22 CD CS L1
SI ES
VOUT
Vcc CIN V+ CT 1
IN+ GND 220uH
25Vdc 100uF RL
3.6k R2 NJM2374A CT 10
470p D1 Cout
R1 DCON 470u
1.2k
0
0
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

7. Step-Up Converter Reference
Circuit Simulation Result
15.0V
VOUT=12V
12.5V
10.0V
7.5V
VIN=5V
5.0V
2.5V
0V
0s 2ms 4ms 6ms 8ms 10ms
V(VOUT) V(Vcc:+)
Time
Evaluation circuit
Rsc 0.22 L1
V+
180uH
RC
180 U1 D1
Vcc CD CS
VOUT
SI ES
5Vdc V+ CT DCON
IN+ GND 1
8.2k R2 NJM2374A CT RL
1500p 250
R1 Cout
953 150u
IC = 11
0
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006

8. Inverting Converter Reference
Circuit Simulation Result
1 -12V 2 12V
-10V 10V
VOUT=-12V
-8V 8V
VIN=5V
-6V 6V
-4V 4V
-2V 2V
>>
0V 0V
0s 10ms 20ms 30ms 40ms 50ms
1 V(OUT) 2 V(Vcc:+)
Time
Evaluation circuit
Rsc
U1
0.22 CD CS D1
SI ES OUT
Vcc CIN V+ CT 1
IN+ GND DCON
5Vdc 100uF L1
953 R2 NJM2374A CT 90uH Cout RL
1300p 250
R1 1 1000uF
8.2k
IC = 11.5
0
All Rights Reserved Copyright (c) Bee Technologies Inc. 2006